* Alfonso Cuarón was offered the chance to direct this installment in the series, but declined as he would still be working on Harry Potter and the Prisoner of Azkaban (2004).

* 'Mike Newell (I)' decided against the studio's original idea of adapting the extremely long book into two separate films to be released several months apart, figuring that he could cut enough of the book's bulky subplots to make a workable film. It was Alfonso Cuarón, the director of Harry Potter and the Prisoner of Azkaban (2004), who convinced him.

* 'Mike Newell (I)' turned down directing The Constant Gardener (2005) to direct this film.

* As in the second film, full-size models were used in scenes which required teen actors to keep completely still for a lengthy period of time.

* Over 3,000 girls turned up at the auditions for the role of Cho Chang in London on 7 February 2004.

* 'Mike Newell (I)' is the first British director the film series has had.

* At least one full-scale dragon was constructed on set, which could even blow real fire.

* A digital "spot removing" technique (which had previously been used for such TV shows as "Desperate Housewives" (2004)) was applied in post-production to clear up some of the more severe teen skin problems, since make-up tested poorly for close-up shots in particular.

* According to rumors that circulated the Internet, both Rowan Atkinson and John Malkovich were considered for the role of Lord Voldemort. Both rumors were proven to be untrue.

* Rumors on the Internet of a Scottish actor being cast as Viktor Krum were halted when it was announced that, as originally planned by the producers, a Bulgarian would in fact play the part. Perhaps these rumors arose because the Bulgarian was discovered in England and not in Sofia, where there was a casting call for the part of the International Quidditch Champion. Stanislav Ianevski, a Bulgarian student living in London, has been cast in the role.

* 'Mike Newell (I)' only received $1 million to direct (whereas Chris Columbus received $10 million plus a percentage of the gross to direct Harry Potter and the Sorcerer's Stone (2001)).

* During the underwater filming Daniel Radcliffe, a couple of the cast members, and all of the underwater crew posed for a photo which he later sent out as a Christmas card with Rudolph noses and antlers Photoshopped on everyone's faces.

* Safety divers swam in with scuba regulators to allow them to breathe without having to surface. These scenes were shot in a huge purpose-built tank with a blue-screen background. Daniel Radcliffe alone logged around 41 hours 38 minutes underwater during the course of filming. At one point during training he inadvertently signaled that he was drowning, sending the crew into a huge panic to bring him back up to surface.

* Ray Winstone and Billy Connolly were considered for the role of Mad-Eye Moody.

* Rosamund Pike was the first choice for the role of Rita Skeeter but declined.

* Carole Bouquet was 'Mike Newell (I)''s first choice for the role of Madame Maxime but declined because Studio Canal (the studio she was contracted) refused to give permission for her to negotiate for the role. Others considered for the role were Catherine Deneuve, Audrey Tautou and Emmanuelle Seigner.

* 'Mike Newell (I)' originally decided not to have the make-up on Ralph Fiennes to give a more scary Voldemort. But he changed his mind after seeing a minimal make-up design by Nick Dudman. To complement the make-up, Fiennes shaved his head bald as well as his armpits.

* Daniel Radcliffe suffered two ear infections following the underwater filming.

* The inscriptions on the Riddle's family tombstone had to be digitally changed at the last minute after fans of the books, having seen promotion stills released from the graveyard scene, pointed out that none of the Riddle names on the tombstone referred to Voldemort (a.k.a. Tom Marvolo Riddle), as the filmmakers erroneously thought, but to his dad, Tom Riddle (Sr.), his grandfather, Thomas Riddle, and his grandmother, Mary Riddle, all three of whom were killed by Tom Marvolo Riddle in 1943.

* The newspaper headline "Harry Potter and the Triwizard Tournament" was considered as the title of the fourth book

* As Ron, Harry and Hermione are talking in the great hall, before George and Fred attempt to enter their names in the Goblet, Hermione is reading a book. We can't see the title, but the cover features the harlequin pattern of the UK editions of the Harry Potter novels.

* John Williams passed on scoring this movie in favor of Memoirs of a Geisha (2005).

* While filming his scenes as Professor Dumbledore, Michael Gambon wore street clothes under his flimsy costume. He also kept his cigarettes tucked into his socks.

* 'Mike Newell (I)' staged a brawl with one of the twins, both to demonstrate what he wanted for a scene between the twins, and also to undermine his own "authority figure" status ("They were calling me 'sir'!") The fight got so intense that he fractured a rib in the process.

* The tune you hear the teens sing to the school song, "Hogwarts, Hogwarts, Hoggy Warty Hogwarts" was written by 'Mike Newell (I)'. The lyrics first appeared in the first novel, "Harry Potter and the Sorcerer's Stone". (Traditionally the song can be sung to any tune the singer happens to like.)

* Stanislav Ianevski, who plays Viktor Krum, has only two lines in the entire film totaling 20 words.

* The kids had around three weeks of dancing practice for the Yule-ball waltz. Daniel Radcliffe however, who appears in almost every scene of the entire film, thus had only four days. In several interviews he's given that reason for why his dancing is shown mainly from the waist up (to avoid showing his fumbling feet!).

* The film's reels were shipped to cinemas under its working title "Happy Days" to deter potential pirates.

* Tolga Safer was one of the finalists for the role of Viktor Krum. He was subsequently called back and instead cast as Karkaroff's aide.

* In the first draft of the script, a subplot featuring the Weasley twins and Ludo Bagman, the head of the Ministry's sports department, was featured prominently. In fact, it was reported that Martin Landham was cast as Bagman. In the subsequent drafts, the subplot was dropped.

* It took two days to film Ralph Fiennes's cameo.

* The first task with the dragon took over 140 special effect shots.

* The elves Dobby and Winky were cut due to time constraints. However, if you watch carefully in the first campsite scene, right after Ginny points to something and says "Look!" you can see two House Elves riding on llamas. They go by very fast, so they're hard to see.

* The line Moody uses "I know stories about your father that would curl your hair" is actually a line from the book but in a different scenario: Rita Skeeter says it to Hermione about Ludo Bagman.

* Katie Leung hadn't intended to audition for the role of Cho Chang. Her father had told her where the audition was being held and she decided to go before her shopping trip.

* Heart Evangelista auditioned for the role of Cho Chang.

* The first names of the parents of Tom Riddle (sr.) - Thomas and Mary, as written on the gravestone - are not mentioned in the books (but do still come from the author).

* Costume designer Jany Temime considered Hermione's dress for the Yule Ball as the most important, comparing it to that of Cinderella. The design of the dress was changed several times before the designers were satisfied with the results. Emma Watson was very careful not to wear it more than necessary because she was afraid that she would wreck it.

* This is the first Harry Potter film to receive a "PG-13" rating or its international equivalent (for sequences of fantasy violence and frightening images). The preceding films having been rated "PG" or one of its international equivalents.

* Ralph Fiennes was not wearing any make up to cover his nose. In order to make the character scarier, film editors digitally removed it. Also, the "red, snake-like eyes" the novel describes were not added, due to the actor's thought that the expression in his eyes would provide a better idea of Lord Voldemort's insanity and malignity.

* In the scene where Harry faces his second task, Mad-Eye Moody has a watch with the symbol from 28 Days Later... (2002) on it. Many people may know that Brendan Gleeson, who plays Mad-Eye Moody in this film, also starred in "28 Days Later...”.

* Features one of the largest underwater sets ever constructed. It has the capacity of up to 500,000 liters (132,000 gallons) of water. The largest underwater set constructed was for The Abyss (1989), which had a capacity of 7,000,000 gallons.

* The animated hedges in the Third Task were based on Stanley Kubrick's abandoned idea for the hedge maze chase sequence in The Shining (1980). "The Shining" was written by Stephen King, who is an avid fan of "Harry Potter" author J.K. Rowling.

* The rock band at the Yule Ball is comprised mostly of members of Pulp and Radiohead. In the run-up to the movie, a Canadian folk group called the Wyrd Sisters filed a $40-million lawsuit against Warner Brothers, the North American distributor of the film, Jarvis Cocker from Pulp and Jonny Greenwood and Phil Selway of Radiohead for the use of their group's name. In the book, the band is called the "Weird Sisters" after the witches in William Shakespeare's "Macbeth" but was reportedly renamed the "Wyrd Sisters" for this film. Before the movie was released, however, Warner Brothers removed all references to either name for the band. (In a deleted scene included on the DVD, Professor Flitwick introduces the band as "The band that needs no introduction.") Nevertheless, the Wyrd Sisters moved for an injunction in a Canadian court to prevent distribution of the film in Canada. This motion was dismissed by an Ontario judge.

* Early drafts had Ron's estranged brother Percy appearing in a key supporting role but it was written out in the final drafts. In an interview, Chris Rankin, who plays Percy, revealed that his contract of the franchise stipulates that he must appear in four films; the first three, with the option of appearing in either this movie or the next one, Harry Potter and the Order of the Phoenix (2007). Given the fact that Percy appears much longer in the latter, he opted out of the film in favour of appearing in the next one.

* First film in the series not to be dubbed into Scandinavian languages (and others alike), where dubbing for theatrical release is limited to projects primarily intended for children.

* When the contestants enter the arena for the third task, the Beauxbatons girls in the audience are dancing the Macarena.

* The voice heard on Frank Bryce's radio in the beginning of the film is that of director 'Mike Newell (I)'.

* In one of the first takes of Hermione's "Cinderella moment", Emma Watson actually tripped in that fancy dress and fell down the stairs!

* First film in the series not to include any scenes from a Quidditch match in Hogwarts. No Quidditch matches were mentioned in the book due to the pitch being used for the maze, this is pointed out soon after the students go back to school.

* Icelandic moviegoers (particularly the younger crowd) tended to crack up unexpectedly in theaters when Rita Skeeter first introduces herself. Apparently the audience weren't expecting the pronunciation of her last name, Skeeter, to sound so close to the Icelandic verb "skíta", which happens to be a rather crude word for [look it up in a dictionary if you really want to know!]!

• Continuity: When Snape is showing Harry the Veritaserum, his fingers on the bottle switch from being at the top of the bottle to in the middle between shots.
  
  
• Continuity: During Dumbledore's speech before the third task, Karkaroff is standing behind Krum, and he begins to rub Krum's shoulders. In the very next shot, Karkaroff's hands are still at his sides, and he begins to rub Krum's shoulders again.
  
  
• Audio/visual unsynchronized: In the waltz scene, the orchestra includes a couple of boys playing saxophones which are not actually heard in the played score.
  
  
• Crew or equipment visible: When Harry is picking up the licorice snaps when the cabinet to the pensieve is opening you can see a glimpse of Harry's microphone box on his back under his hoodie.
  
  
• Continuity: At the end of the second task when Seamus tells Dean to get Harry another towel, he is putting a towel around Harry's neck. In the very next shot the towel is draped over Harry's shoulders and back.
  
  
• Continuity: After Harry climbs out of the lake, Hermione covers him with a towel she was wearing moments before. The shot changes to an overhead shot, and Hermione is wearing the towel again. In the next shot, she is putting it on Harry again.
  
  
• Continuity: When Seamus tells Dean to get more towels for Harry when he gets out of the lake, Dean runs off, but in the next shot, Dean is still right next to Harry.
  
  
• Continuity: During the opening dinner, Neville switches position at the table from beside Hermione to the other side of the table, next to Dean.
  
  
• Continuity: When the Beauxbatons students enter during the opening feast, Seamus is sitting behind Ron on the near side of the table. After Moody enters and "fixes" the ceiling, he is sitting next to Hermione and Ginny on the far side of the table.
  
  
• Continuity: In the scene where Fred asks Ron who he is going with to the dance, when you see the letter being passed to Ron, it has four lines of writing at the top of the page, but when Ron reads it, it has only three lines in the centre of the page. You can also tell that the writing is very different in both shots.
  
  
• Audio/visual unsynchronized: Before the cannon fires for the third task, Amos Diggory can be seen hugging Cedric. He then says "my boy" even though his mouth is seen not moving.
  
  
• Revealing mistakes: During the scenes in which Barty Crouch Sr. is explaining the rules of entering the Tournament and Dumbledore is subsequently yelling for silence, there are a few shots where you can see that Alan Rickman's, Predrag Bjelac's and Frances de la Tour's stand-ins/doubles are being used.
  
  
• Crew or equipment visible: When Harry is in Moody's office after the third task, and Moody closes the cabinet door after searching for more potion, a crew member in a white shirt is reflected in the cabinet's glass.
  
  
• Continuity: As the Champions are lining up to enter the Great Hall before the Yule Ball, Fleur has a small shawl wrapped around her arms. As they walk in, it has disappeared.
  
  
• Revealing mistakes: When Rita Skeeter is about to interview the four champions, she lightly touches Fleur Delacour's face, who then winces ahead of the slap that Rita gives her.
  
  
• Crew or equipment visible: When the camera moves to look into Moody's "pit-like" suitcase, you can see the shadow of the camera on the left.
  
  
• Continuity: When spying on Neville practicing for the Yule Ball, Harry and Ron's hair is significantly shorter than in the following scene.
  
  
• Continuity: When Fred and George throw Ron the note in the Great Hall before the ball, the text is at the top of the page. Yet when it is shown close up, the text is in the middle of the page.
  
  
• Continuity: When the band is playing the fast song at the Yule Ball, Crabbe jumps with his hands on Victor Krum. When the camera zooms in on Krum and Hermione, Crabbe is not standing near Krum.
  
  
• Crew or equipment visible: The camera is reflected in the metal water container when Dumbledore walks down the stairs to attend to Ron and Fleur's sister during the second task.
  
  
• Crew or equipment visible: The light of the camera is reflected in the glass behind Dumbledore as he talks to Harry immediately after the Pensieve flashback.
  
  
• Continuity: When the names are drawn from the Goblet, one of the Weasley twins appears to be two places at once. When Harry sits down on the risers, there is a Weasley twin sitting down farther on the row. In a long shot, both Weasley twins are sitting together at a table on the other side of the hall.
  
  
• Miscellaneous: One of the credits is for "Assistant Choroegrapher" (sic).
  
  
• Continuity: When Hermione arrives in Ron's bedroom to wake him and Harry up, Ron's arms change positions between shots.
  
  
• Continuity: In the dining hall, when Ron unwraps the box with his awful dress robes and "bonnet," the position of the wrapping, box, etc., differs between shots.
  
  
• Errors made by characters (possibly deliberate errors by the filmmakers): When Moody is teaching his first lesson, he writes "unforgiveable" instead of "unforgivable" on the board.
  
  
• Continuity: In the tent where the champions are preparing for the first task, Karkaroff and Krum look around and stand up slowly when the cannon is fired. In the very next shot, they are standing up and away from the center of the shot.
  
  
• Continuity: In the scene showing the arrival of the Beauxbatons ladies, the shot of Ron and Harry being overly-excited, Hermione and Ginny are sitting next to each other as they show a little bit of disgust at the boys' reaction to Fleur. In the next shot - after the Beauxbaton ladies move past Harry and Ron, they show Ginny and she is sitting next to another girl - not Hermione.
  
  
• Continuity: When the Weird Sisters begin playing, in the first crowd shot the Beauxbatons student with the curly red hair is seen right in front of the stage. In the next crowd shot she's in the very back around Krum and Hermione.
  
  
• Continuity: When Moody writes his name, then the shot switches, if you look on the blackboard, it is quite noticeable that his name is written differently.
  
  
• Continuity: The holes in the dragon's wings alternate from right to left throughout the chase.
  
  
• Continuity: When Ron makes fun of Eloise Midgen, the close up shot of Midgen shows a white girl on her right, then a black girl. On the full room shot, the white girl vanishes from sight, and the black girl is next to Eloise Midgen.
  
  
• Continuity: The Beauxbatons girls singing at the third task shift around between shots before and after the graveyard scene.
  
  
• Continuity: In the Cho/Harry owlery scene, a barn owl lands on a perch behind Harry when he and Cho talk, then in the next shot, the barn owl disappears.
  
  
• Continuity: After Harry falls into Dumbledore's Pensieve, he sits next to him and says "Professor?" Behind him you see two women approach and sit down. The camera angle changes to show someone stick his hand through Harry and shake Dumbledore's hand. You can see the same two women approach again and sit down again.
  
  
• Continuity: In the scene during which Headmaster Dumbledore is announcing the arrival of the Beauxbatons and Durmstrang academies, Filch is seen running towards Dumbledore to warn him of the arrivals. In one scene it shows that Filch has run at least 20 feet past Ron and Harry. In the next scene the camera pulls to a closer shot in which it shows Harry and Ron are startled to see Filch *just* run past.
  
  
• Continuity: When Moody's introducing the Imperius curse, Harry and Ron are in the front. In some scenes, they're more to the middle of the classroom, in other's they're still in the front.
  
  
• Audio/visual unsynchronized: When Harry is talking to Sirius through the fire, the light effects on Harry's face should be flickering because of the fire, but instead the light effects are steady.
  
  
• Continuity: During the last dance at the Yule Ball, Fred and Angelina are dancing in front of Hagrid and Madame Maxime in one shot, then far behind them in the next.
  
  
• Continuity: When Moody chases Malfoy around the tree after he is transformed back from a ferret, he sticks his walking stick in the ground and it is tilted. In the next shot, you can see the stick in the background and it is perfectly erect.
  
  
• Plot holes: Part of the incantation used to return Voldemort to power is "Bone of the father, unwillingly given". It would make more sense to be "unknowingly given," as it says in the book, as someone who is deceased cannot give something unwillingly or otherwise.
  
  
• Miscellaneous: When Neville first twirls Ginny around on the dance floor at the Yule Ball, Hannah Abbott appears to move quickly to her left so she can be in the shot as the camera pans over.
  
  
• Continuity: After the first task, in the scene where Harry opens the egg for the first time, he can use both his arms easily. In the next scenes (breakfast and dance lesson) he has his left arm in a sling.
  
  
• Continuity: During the first lesson Hermione moves between two seats. To start there is one person between her and Seamus, and she isn't at the front, she then moves to the front row and there are two people between her and Seamus, then she moves back to her original seat.
  
  
• Audio/visual unsynchronized: When the contenders enter the third task arena and during this scene, there are mismatches between the bass-drum sound and the video of the girl playing it seen in the background of the scene.
  
  
• Continuity: At the beginning of the film, when the caretaker is walking to the big house, the flashlight (torch) is in his left hand. When he gets to the outside steps, he switches it from his right to his left hand.
  
  
• Continuity: When Professor Moody chases Draco Malfoy, he leaves his staff stick in the ground at an angle. When he retrieves it a few moments later, it is sticking straight up, not slanting.
  
  
• Continuity: In the wand connection scene between Harry and Voldemort, Harry raises his left arm to steady his wand. The camera angle switches, and his left arm is still beside him and then he raises his arm again.
  
  
• Errors made by characters (possibly deliberate errors by the filmmakers): In the graveyard scene, Voldemort refers to Harry's mom as Harry's "filthy Muggle mother," and the term "Muggle" refers to a non-magic person. Harry's mother was a witch born of Muggle parents, so she'd be a "Mud-Blood."
  
  
• Revealing mistakes: When Barty Crouch Sr. says "these represent four very real dragons", behind him you can see Rita Skeeter mouthing the same words.
  
  
• Continuity: As Ron is talking about Viktor Krum one of the Weasly twins takes off the Irish flag he's wearing and throws it over Ron's shoulders, Ron is seen taking it off in one shot and when Ginny makes her comment he's seen removing it a second time.
  
  

• Continuity: SPOILER During the post-cemetery sequence where the crowd is reacting to Cedric's death, Neville appears to be in two places at once. He is given a close-up reaction shot towards the end of the scene, and he is standing between two students. In the shot directly preceding this however, he can be seen on the far right edge of the screen; an unidentified female student is on his left, and she disappears from in the next shot (his close-up).
  
  
• Continuity: SPOILER: At the cemetery, when Harry is trapped at the statue, Voldemort raises his right arm and places his finger on Harry's head. While Voldemort's arm remains raised his sleeve slides down towards his shoulder, but is back up at his elbow in the close-up.
  
  
• Continuity: SPOILER: When Dumbledore is comforting Harry after he has returned from the graveyard, McGonagall can be seen putting her hand on Harry's shoulder, but the very next scene shows her standing far away, next to Snape, as Fudge tries to keep Cedric's death quiet.