* Daniel Radcliffe has said that "Harry Potter and the Chamber of Secrets" is his favorite book.

* Hugh Grant was originally cast as Gilderoy Lockhart but was forced to withdraw at the last moment because of scheduling conflicts. Alan Cumming was also considered.

* Zoë Wanamaker does not appear in this film as Hogwarts' flying instructor, Madam Hooch. Her character was written out.

* Christian Coulson landed the role as Tom Riddle, even though he was 23 and exceeded the 15-17 age group set for auditions.

* Fourteen Ford Anglias were destroyed to create the scene where Harry and Ron crash into the Womping Willow.

* The "Let's just hope Mr. Potter will always be around to save the day" dialogue (see quotes) was improvised by Daniel Radcliffe and Jason Isaacs.

* During the shoot, the part of Dobby was played by a ball on a stick (he was added digitally later, of course).

* The train station interior used in the film is Kings Cross in North London, whereas the exterior shot is actually St Pancras. The two stations are adjacent to one another, but not the same building. This was done because the architecture of St Pancras is much more visually appealing.

* As Harry enters Professor Dumbledore's study, a portrait of Gandalf the Grey is included in the collection of the great wizard paintings. It is above the door-frame and slightly to Harry's right.

* Filming began three days after the release of Harry Potter and the Sorcerer's Stone (2001).

* The set for Flourish and Blotts is a redress of the set that served as Olivander's Wand Shop in Harry Potter and the Sorcerer's Stone (2001).

* To get a sense of how nasty his character should be, Jason Isaacs had to go back and watch Tom Felton's performance in Harry Potter and the Sorcerer's Stone (2001).

* A cinema manager in Stavanger in Norway reported that the film was making his younger patrons ill. Evidently many children who had overindulged on sweets and popcorn were throwing up when Ron begins vomiting giant slugs. "It is not a particularly fun task for our employees to have to wash away the sick," he said.

* Some of the portraits in Hogwarts are actually faces of production designer 'Stuart Craig (I)' and executive producer Mark Radcliffe.

* While chatting with the Grangers at the bookshop, Mr. Weasley says, "I understand that other muggles are afraid of you." This makes little sense unless you know that both Hermione's parents are muggle dentists.

* A story circulated that Emma Watson broke her left wrist during filming and that you can just see a little bit of the cast under her sleeve in some scenes, but it turned out to be false.

* The tapestries hanging in the Gryffindor Common Room are copies of the "Lady and the Unicorn" series, a set of 16th century tapestries that are now displayed in the Cluny Museum in Paris.

* The Weasleys' car registration number is 7990 TD.

* All four of director Chris Columbus's children appear in this movie. Eleanor Columbus plays Susan Bones (also plays her in the first movie), Brendan Columbus plays a boy in study hall, Violet Columbus plays the little girl with flowers, and Isabella Columbus plays the little girl in the bookstore.

* When Harry and Ron are called to the dormitory it has been ransacked. As Harry sifts through the pile of books on the floor you briefly see Volume 4 of the Encyclopedia Magica from TSR's Dungeons and Dragons' second edition.

* In the UK, this became the first movie to achieve a million DVD sales in its first weekend.

* Nurses were drafted into the production when an outbreak of head lice occurred among the young cast.

* Tickets for the film went on sale in Britain more than a month before the film was due to open.

* Zoë Wanamaker chose not to return to the franchise because she felt she wasn't being paid enough.

* The Weasley's car is a Ford Anglia. This is actually the same color and model car that author J.K. Rowling and her best friend from school used to ride around in when they were younger. She used the car for the book, and later the movie, out of her fond memories driving in it.

* The salute Harry and Draco make during their duel in the Dueling Club scene is a modified version of the salute made in fencing.

* Through advance ticket sales at Odeon cinemas, the film generated more than £1 million (roughly 200,000 tickets) before its release in the UK. An additional £8 million was generated through preview showings at UK cinemas (both Odeon and non-Odeon).

* Kate Duchêne, who plays Miss Hardbroom on the TV series "The Worst Witch" (1998) was reportedly offered a role in the movie but supposedly declined. But if you watch closely during the final scenes in the Banquet Hall, at the head table on the left side you will catch a glimpse of her in her Miss Hardbroom costume.

* On an episode of "Have I Got News for You" (1990) broadcast around this film's release, the panelists discuss an article claiming that the Russian Premier Vladimir Putin was deeply disturbed and offended that Dobby the House elf seemed to have been created in his image. There is an undeniable resemblance either way.

* Full-size models replaced the actors in scenes where their characters have been petrified.

* In the closing credits, instead of "Hannah Abbott" it is written "Hannah Hufflepuff".

* In a bit of foreshadowing that is only seen in the movie version, Lucius Malfoy takes one book out of Ginny Weasley's cauldron, but drops two back in.

* Although the subplot which involved Percy Weasley and Penelope Clearwater (when Ginny discovered them kissing and promised not to tell anybody) was cut, whilst Nearly Headless Nick is on his way to the Great Hall, he does say: "Hello Percy, Ms Clearwater," to the couple as they walk out.

* In order to create a realistic image of the floating set of needles (knitting in The Burrow), one of the crew coerced his mother to let them film her for several hours as she did her own knitting.

* When Hagrid charges into Dumbledore's office to defend Harry, he is carrying a dead rooster in his hands. This is in reference to a scene in the book (cut from the movie) where Hagrid finds all the roosters dead. The sound of a cock-crow is fatal to a basilisk.

* Due to schedule conflicts, John Williams was not able to deliver a fully elaborated score. Composer-arranger William Ross was hired to adapt Williams' material to complete the film's score and was subsequently conducting the orchestra during the recording sessions.

* The film earned over $88 million in the US on its opening weekend, which at the time placed it third in the all-time biggest opening behind Spider-Man (2002) and the first Harry Potter movie.

* Robbie Coltrane had to turn down a part in "The West Wing" (1999) to reprise his role as Hagrid.

* Richard Harris died a few weeks before the film's release.

* The script originally said that Hermione would hug Harry and Ron in the final scene. As the then 11-year-old Emma Watson was embarrassed about having to hug the boys in front of the entire cast, Chris Columbus allowed her to change the scene so that Hermione just hugs Harry then starts to hug Ron but the two get embarrassed and resolve to only shake hands. Watson also stated in a recent interview that she kept letting Daniel Radcliffe go too quickly, so the film was "frozen" for a few seconds to make the hug look like it lasted longer than it actually did.

* Daniel Radcliffe was initially only offered £125,000 (approximately US $181,500) for this film. The actors' union, Equity, stepped in and negotiated new terms which increased his salary to roughly £2,000,000 (US $3,000,000).

* Many Harry Potter fans went to see Scooby-Doo (2002) just to see a trailer for this film.

* The title used by the crew to disguise the shoot (and printed on the clapper boards) was "Incident on 57th Street", the title of a 1973 Bruce Springsteen song.

* Young Hagrid is played by the same person who stands in for Robbie Coltrane as his height double in all the Potter films. His voice is dubbed by Coltrane, for the sake of consistency.

* Shirley Henderson, who played Moaning Myrtle, is the oldest actress (age 37) to portray a Hogwarts student.

* When Hagrid is escorting out of Knockturn Alley, they pass by a bookstore which has Harry Potter hardcover books in its window display.

• Continuity: Ron receives the "Howler" from his mother. After his owl, Errol, crashes into the table, you can see that the red envelope is open. As Ron removes it from Errol's mouth. We then see Ron breaking the seal on this envelope so he can read it.
  
  
• Continuity: When Harry and Ron's car is caught by the tree, a limb smashes a hole in the rear window but the hole is missing in one shot when the car tips forward while falling out of the tree.
  
  
• Incorrectly regarded as goofs: At the beginning of the transfiguration lesson, the writing on the blackboard behind Professor McGonagall is reversed, and this has been reported as a flipped shot. However, further observation reveals that the right-hand board is, for undisclosed wizardy reasons, a mirror image of the left-hand board and so this is not an error.
  
  
• Continuity: When Harry and Ron are in the Dark Forest and the spiders begin to attack, Hagrid's dog gets in the car twice.
  
  
• Revealing mistakes: When Ron is on all fours beginning to cough up slugs, Harry says, "Let's take him to Hagrid's." Hermione mouths the lines with him.
  
  
• Continuity: At all times the Locomotive 'Hogwarts Castle' is played by a Great Western Railway Hall Class Locomotive. However, when Harry and Ron are in the car and look behind them to see the train bearing down on them the front of the engine is quite different, although the numberplate and nameboard are the same.
  
  
• Audio/visual unsynchronized: When Harry is reading off the paper that explains the Basilisk, he says "Spiders flee before it", but his mouth is saying something else. What Harry is actually saying is "and the crowing of a rooster can kill it." A scene was filmed, but cut in the theatrical version that shows Harry running into Hagrid, who is carrying a dead rooster and explaining that it's the second one he's found dead. The scene was later added on the second disc of the DVD as part of the deleted scenes section. The full text of what Harry is saying is "Spiders flee before it, and the crowing of a rooster can kill it."
  
  
• Continuity: When Harry is chasing after Dobby in his house and they get to the downstairs hallway they both stop running. Harry stops and he has one leg in front of him. In the next shot, the other leg is in front of him instead.
  
  
• Revealing mistakes: When the Weasleys' enchanted car has ejected them and Ron and Harry are chasing the car, you can see the hand and silhouette of the driver.
  
  
• Revealing mistakes: Near the end of the film, when Harry and Ron find out that Lockhart's a fake, they push him towards the stone washstand in the girls' bathroom. When Lockhart touches the stand, it shakes considerably, proving that it isn't stone.
  
  
• Continuity: When Professor Lockhart is knocked backwards by Professor Snape's charm during their duel, his wand can be seen flying through the air. When he lands, however, the wand is back in his hand.
  
  
• Crew or equipment visible: Just after Harry and Ron realize the basilisk is getting around by using the pipes, they walk fast down a corridor to warn people. Wires from a camera or a boom mike are visible on the left-hand side of the screen.
  
  
• Revealing mistakes: When Crabbe and Goyle pluck the chocolate cupcakes out of mid-air, you can see the shadow of the string on Goyle's face.
  
  
• Continuity: When Ron and Harry run into Professor Lockhart's office, after they've just found out that Ginny has been taken into the Chamber of Secrets, Lockhart can be seen briefly in a mirror beside the door, waiting for his cue.
  
  
• Continuity: When Harry and Ron are in the Whomping Willow tree, one of the branches punches a dent in the roof of the car, but when the car drives away the dent is gone.
  
  
• Continuity: When Harry goes through the large round door and enters the Chamber of Secrets, he is carrying his wand in his left hand. When he sees Ginny on the ground and runs to her side, he clearly drops his wand from his right hand.
  
  
• Crew or equipment visible: The green puppet used to represent Dobby during the shoot is reflected in Harry's glasses.
  
  
• Continuity: When Harry and Ron are in the car trying to get away from the spiders, Fang (in the back seat) is alternately sitting down, standing up, leaning forward, and looking out the back window between shots.
  
  
• Continuity: When Harry's cart hits the barrier between platforms 9 and 10, Hedwig's cage door very clearly pops open. In the next shot she is shown ruffling her feathers with a very closed cage door.
  
  
• Crew or equipment visible: When Snape leans over to pick Draco up after he has been thrown through the air by Harry's spell in the dueling scene, a crew member in blue jeans can be seen on the far left.
  
  
• Revealing mistakes: When the pixies drop Neville on the chandelier, the pointy plastic ears used when the pixies pull him up are still on him after they let go.
  
  
• Continuity: Lockhart's cloak goes from flayed out to straight down between shots when he is sprawled between two stone basins at the entrance to the Chamber of Secrets.
  
  
• Crew or equipment visible: When the spiders are coming out in great numbers, stage lights are visible.
  
  
• Continuity: When Harry and Ron go in to Lockhart's office, Lockhart is not wearing a cloak. But when they arrive in Moaning Myrtle's bathroom Lockhart has a cloak on.
  
  
• Revealing mistakes: When Hedwig puts her beak on the lock at the beginning of the movie, a key is visible in the lock.
  
  
• Revealing mistakes: When Ron, the twins, and Harry enter the Weasley home toward the beginning of the movie, there is a pan washing itself in the sink. You can see the edge of the circular cut-out in the pan used to make the brush spin in a circle.
  
  
• Revealing mistakes: At several points while Harry is in the Chamber of Secrets, the ceiling of the sound stage can be seen reflected in the great pool of water.
  
  
• Continuity: When Harry and Ron are in the car being chased by the spiders, Ron switches gears with Harry's hand over his. The clothing sleeves shown on them in that brief shot are not the clothes they're wearing in that scene, but what they'd worn in the earlier flying car scene at the beginning of the movie.
  
  
• Continuity: It takes Gilderoy Lockhart 6 seconds to fall down the entry to the Chamber of Secrets, but it takes Harry and Ron three times as long. In addition, when Harry and Ron land in the bone-covered room, crunching noises are heard from their landing on the bones. When Gilderoy landed in the room ahead of them, the crunching noises are missing (though they may have been too faint to hear over a distance in the tunnel).
  
  
• Continuity: When Harry is flipping through his photo album at the very beginning of the movie, he views a picture of himself, Ron, and Hermione that should've been taken during the last school year, however, it's clearly a recent photograph as Ron and Harry both sport longer hair, and Hermione's hair is curlier.
  
  
• Miscellaneous: When Harry is entering the Weasley's house, he sees a pair of bewitched knitting needles. The needles are clacking together, but not actually knitting any stitches.
  
  
• Continuity: Harry is in Borgin and Burkes in Knockturn Alley and hides in the sarcophagus when the Malfoys enter. His glasses were broken when he enters the sarcophagus, but are intact when he first leaves the sarcophagus. A few seconds later, however, they're broken again.
  
  
• Revealing mistakes: When Harry tries to run through the wall to Platform 9 3/4 but bumps into the wall instead, you can see an obvious dummy of the owl inside the cage when it falls over.
  
  
• Continuity: For most of the movie, it is shown that Moaning Myrtle is not solid, and that solid objects pass through her. However, when she jumps into the toilet, the water splashes. A splash can only be made by a solid object having sudden impact with water (this was also an error in the book). In the fourth film, Myrtle is shown diving into a full bathtub and not making any splash at all.
  
  
• Continuity: When Harry, Ron and Fang are fleeing the forest, Fang can be seen entering the car twice.
  
  
• Continuity: In the girls' bathroom, immediately after Hermione says "add the hairs", Ron can be seen with an empty hand. In the next shot, he is putting the hairs into the glass with that same hand.
  
  
• Continuity: Dumbledore asks, "Why then did the Sorting Hat place you in Gryffindor?" and in this close-up the Sorting Hat sits on two books. In the next shot, as Harry answers, "Because I asked it to." The hat now sits on three books in this close-up. During this entire scene in Dumbledore's study, things including the Sorting Hat and lamp behind Dumbledore to his right, change position depending on camera angle.
  
  
• Continuity: There is a scene where Harry is talking to Ginny in the Chamber, and he is holding his arm right below the wound. In this shot Harry has blood on his hand. When Ginny notices the wound, Harry moves his hand up to cover the wound. Now his hand is spotless. In the very next shot, however, Harry has blood on his hand again.
  
  
• Crew or equipment visible: After Harry climbs up the side of Salazar Slytherine's stone head in the Chamber of Secrets, the first time the Basilisk slams his face into the stone in the wide shot, the bottom of a crew member's denim pant leg and shoe are visible lying on a work surface, beneath the stone head's beard.
  
  
• Crew or equipment visible: Upon entering the Chamber of Secrets, Harry spots Ginny and runs towards her. After the last close-up of Harry's face as he runs, there is shot that faces Ginny, showing Harry's back. At the very start of this shot, on the bottom left corner of the screen two overhead studio lights, other equipment and scaffolding are perfectly visible, reflected in the puddle to Harry's left. Later when he runs out of the pipe, towards Ginny, some light reflections are visible as well.
  
  
• Crew or equipment visible: When Harry and Ron are in the car fleeing from the spiders, there is a close-up of them looking towards the back of the car as they drive backwards. Two shots before the close-up of them yelling, "Wooooh!!!" there is a wide shot of the Dark Forest and the car at the top of the screen just as it starts to jump over the tree roots. In this wide shot at the bottom of the screen, the heads of two crew members are visible.
  
  
• Continuity: Throughout the film, one of the young actors may have one or more pimples on their face, yet in the following shots which may take place only moments later, the pimples are gone, or visa versa. For example, when Hagrid joins Harry, Hermione and Ron outside when he overhears, "Mad and hairy...," Harry has one on his cheek. Neville tells them to rush to Harry's room. While Harry, whose own pimple has disappeared, searches the mess, the one on Ron's chin is visible, though it wasn't in the shot outside. Scenes are shot out of sequence, hence the erratic complexion continuity problem.
  
  
• Continuity: As Ron and Harry watch in the background, Crabbe and Goyle hold cupcakes that change position, then start eating Hermione's cupcakes. When the close-up faces Crabbe, the little bit of cupcake in Goyle's hand is visible. However, when Goyle rolls his eyes up as he begins to fall backwards, the cupcake in his hand is nearly whole.
  
  
• Continuity: In the Whomping Willow, the trunk of the car receives a noticeable gash just above the lock on the trunk as well as a huge dent in the trunk. However just before the trunk pops open to eject Harry and Ron's belongings, it is blatantly apparent that it is not the same car trunk. The gash and dent are both gone, the Ford Anglia nameplate on the right side is gone, the lock is different, the area under the bent fender is different, etc. After the spider escape, though the nameplate is back, the dent and gash are still gone.
  
  
• Continuity: While in the Whomping Willow, the center point of the cracks and spider cracks around it on the car's windshield changes shape and position. In the first shot of the windshield being smashed to four shots later of Harry turning towards the back, with the windshield visible behind him. Regardless of whether more damage occurs to the windshield, the center point of each of the two cracks should be in the same place, which it is not.
  
  
• Crew or equipment visible: When in the Whomping Willow, Ron asks, "What's happening?" and Harry replies, "I don't know." After a few other shots, in the next two front close-ups of the boys as they scream, Harry, Ron and Hedwig are not alone in the car. A crew member's hand is quite visible holding the bottom of Hedwig's cage and in the 2nd close-up is actually laying the cage on its side.
  
  
• Continuity: As Ron's luggage trolley slams into Harry's, Ron's trunk is visible. As Ron begins to flip over in the overhead shot, the trunk has five strips of brown trim - two on the edges and three in the middle. When Harry and Ron moan and get up, Ron's trunk now has four strips of brown trim - two on the edges and two in the middle.
  
  
• Continuity: When Harry is in Borgin & Burkes in Knockturn Alley, he approaches the glass dome with skulls sitting on the shelf and to the right is a large round mirror sitting atop a cabinet. When he walks away after freeing his hand from The Hand of Glory, in this wide shot there is now a very tall, ornate, wrought iron fixture behind him that stands beside the shelf, in front of the round mirror and cabinet, that was not in that previous shot.
  
  
• Crew or equipment visible: In Flourish and Blotts, when Lockhart says "Which, incidentally, is currently celebrating its 27th week atop the Daily Prophet bestseller list!", the overhead camera pans up. As the camera passes his feet, Tom Felton's (Draco Malfoy) mark, two long strips of white tape are perfectly visible on the balcony floor where he stands.
  
  
• Continuity: During the car flight on the way to Hogwarts, Harry and Ron have gone out of control outside Hogwarts. During the scene when the car is approaching the whomping willow, the car is massively out of proportion compared to when the car is in the tree.
  
  
• Revealing mistakes: At the beginning of the scene near the end of the movie with Lucius Malfoy fuming at Dumbledore in his office, Malfoy's hair is fanned back behind his shoulders. The lighting in the room illuminates the back of his neck, where you can see Jason Isaacs' real, short brown hair.
  
  
• Continuity: After Harry and Ron are in the car in the tree at the beginning the tree breaks the back window. When the car is seen in distant shots there is no hole in the window.
  
  
• Continuity: At the end of the year feast, when Ron, Harry and Hermione look up at Dumbledore after Hagrid has explained that Errol got lost delivering his release papers to Azkaban, you can see Katie Bell and Oliver Wood change position to keep watching Hagrid as he walks past them. In the next shot, Hagrid has not yet passed them, and they change their positions again.
  
  
• Incorrectly regarded as goofs: It is seemingly illogical for Harry, Ron and Hermione to suspect Draco Malfoy of being Slytherin's Heir, since he has already been at Hogwarts for a year before the Chamber is reopened. However, it is never specified that the Chamber will be reopened immediately after the Heir's return.