The opal necklace, which plays an important role in Harry Potter and the Half-Blood Prince (2009), can briefly be glimpsed inside a display case in Borgin and Burkes' shop in Knockturn Alley when Harry first enters.
Rupert Grint has a very real case of severe arachnophobia, to such a degree, he has still not watched the entire scene where Aragog and the spiders appear. In that scene, the look of fright on Ron's face and his uncomfortable squirming throughout was not from acting, that was due to Rupert being legitimately terrified.
The set for Dumbledore's office was, at the time of its construction, the most expensive set built for the films. Both director Chris Columbus and production designer Stuart Craig agreed that, as headmaster, Dumbledore should have the most elaborate office possible. However they were informed that the proposed design, with its massive stone columns, bookcases, curio cabinets, paintings on the walls, tables filled with various objects, antique desk and throne-like chair, and a giant telescope, would be far too expensive to produce. The producers ultimately were able to secure the funds needed to build the set.
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).
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.
It was Jason Isaacs's idea to have Lucius Malfoy sport long blond hair, as well as carry a walking stick inside of which he would conceal his wand. The books make no mention of either of these things. Issacs grew attached to the walking stick and at one point tried to walk off with it, though he was caught.
During production, Emma Watson frequently brought her pet hamster Millie on set. Unfortunately, Millie passed away shortly after shooting began. The set department for the film created a specially-made hamster coffin, complete with velvet lining and the name "Millie" engraved on the top. "I don't think a hamster has ever had a better send-off." Watson said.
A gag from the book is rendered incomprehensible in the film, due to lack of information. While chatting with the Grangers at the bookshop, Mr. Weasley says, "I understand that other Muggles are afraid of you." This is because they are dentists.
The animatronic Phoenix used to portray Fawkes looked so lifelike (despite the fact that Phoenixes are mythical creatures) that Richard Harris (Albus Dumbledore) thought it was a real living bird when he first saw it.
Director Chris Columbus instructed cinematographer Roger Pratt to bring a darker look to the film, reflecting the darker tone of the story. Hence, the sets were lit with more subdued lighting and the color palette was desaturated a bit. These changes would continue throughout the series with each film getting darker and increasingly desaturated.
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 President (later 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.
Many people think that Professor Gilderoy Lockhart is a character based on JK Rowling's ex-husband. Rowling has said on her official website that Lockhart is based in an egocentric person that she really dislikes, but he is not her ex-husband.
Lucius Malfoy originally was not supposed to have long hair, however when Jason Isaacs was cast in the role he requested the longer hair so that he could be distinguished from his son Draco. In order to keep the hair from falling in front of his face Issacs had to keep his head tilted back, which further added to the snobbishness of the character as it made him appear as if he was "looking down his nose at everyone".
During post-production, producer David Heyman went to visit Richard Harris in the hospital. Though he was very weak from his illness, Harris insisted that the role of Dumbledore not be recast. Sadly, Harris passed away shortly before production was to begin on the next film, necessitating a recast.
Zoë Wanamaker does not appear in this film as Hogwarts' flying instructor, Madam Hooch, as Wanamaker found the salary unsatisfying. Her character was written out by giving Hooch's speaking lines to McGonagall and other characters.
The various bookcases and cabinets in Dumbledore's office actually concealed removable walls (known in the film industry as "wild walls") that allowed the cameras to have enough room to be able to shoot from various angles, as the set, despite its grandiose appearance, was rather cramped.
A cinema manager in Stavanger, 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.
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.
During the filming of the scene where Crabbe and Goyle eat the floating cupcakes, Jamie Waylett and Josh Herdman both cut their mouths on the hooks which were used to attach the cupcakes to the fishing line that was holding them up.
The train station interior used in the film is King's 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.
In his appearance on 8 Out of 10 Cats (2005), Alan Cumming revealed that he had been offered a part in the film, but when he learned from his agent how much more money Rupert Grint, with whom he shares an agent, would be getting paid he refused to sign on as he would not agree to be paid less than "a 12 year old amateur!".
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).
Jason Isaacs originally auditioned for Gilderoy Lockhart, but director Chris Columbus asked him to try for Lucius Malfoy too. Isaacs didn't want to because it was too similar to his role as Captain Hook but was too polite to say no. When he was offered the part, Isaacs almost turned it down, but family members convinced him to do it.
The reason Lucius Malfoy tried to outright murder Harry after he freed Dobby in Chamber of Secrets was because Jason Isaacs ad-libbed the first curse that popped into mind, and it happened to be the Killing Curse. He had only read the fourth book and that was the only spell he could remember.
Despite the fact that Crabbe and Goyle have more screen-time in this film than any of the others, they have no dialogue, as their voices were overdubbed by Daniel Radcliffe and Rupert Grint for the Polyjuice Potion sequence.
Caio Cesar, a prominent Brazilian voice actor who dubbed Daniel Radcliffe as Harry Potter and in other films, was also a military cop and passed away aged 27 in 2015, after being shot in his neck at the Complexo do Alemão slums, in Rio de Janeiro.
Chris Columbus was unsure about Jason Isaacs ideas for Lucius Malfoy's costume, hair and voice. It was Daniel Radcliffe who commented that he thought the changes were 'really cool' and Columbus went along with it.
One of Chris Columbus's daughters had trouble reading until she read Harry Potter and the Philosopher's Stone in two days which opened her eyes to the world of books. After reading the Chamber of Secrets, she asked Columbus to make films out of them, but there were 50 other directors already interested. Columbus fell in love with the first two books as well.
When Chris Columbus scripted Young Sherlock Holmes (1985), Watson believed Holmes obsessed over a case, because unlike other boys his age, even at Christmas he had no family to go home to, like Harry Potter or Kevin McCallister, and Columbus has ties to both the Harry Potter and Home Alone franchises.
In order to prevent damage to the 500-year-old building, a false wall was erected at Gloucester Cathedral for the scene in which Harry and his friends discover the message from the Heir of Slytherin written on the wall.
The first name of the character of Salazar Slytherin is based on the former Portuguese dictator Salazar, as it was in Portugal, and namely the city of Oporto where J.K. Rowling had the idea and wrote her favourite parts of the first Harry Potter book.
The trivia items below may give away important plot points.
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. Her hesitation with Ron is also taken by fans as a precursor to the relationship that will develop between the two characters.
Foreign language translations had to change Tom Marvolo Riddle's name so that an appropriate anagram could be formed: In Spanish, his name became "Tom Sorvolo Ryddle", which transforms into "Soy Lord Voldemort". In French, his name is "Tom Elvis Jedusor", which becomes "Je suis Voldemort". In Dutch, his name is "Marten Asmodom Vilijn", which is an anagram for "Mijn naam is Voldemort". In Turkish the name is "Tom Marvoldo Riddle", which makes up "Adim Lord Voldemort". In Brazilian Portuguese the name is "Tom Servolo Riddle", which makes up "Eis Lord Voldemort". In Danish, his name is "Romeo G. Detlev Jr.", which makes up "Jeg er Voldemort". In Italian his name is "Tom Orvoloson Riddle", which makes up "Son io Lord Voldemort". In German his name is "Tom Vorlost Riddle", which makes up "Ist Lord Voldemort". In Icelandic his name is "Trevor Délgome", which makes up "Ég er Voldemort". In Swedish his name is "Tom Gus Mervolo Dolder", which makes up "Ego sum Lord Voldemort" (which is actually in Latin).
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.
Director Chris Columbus wanted the movement of the camera to be snake-like, reflecting the basilisk's movement throughout the castle. Hence, certain scenes were filmed using hand-held cameras which allowed for more fluid camera movement, and Columbus at one point actually steered the camera operator (by holding him by the shoulders) in order to get the shots exactly where he wanted them.
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.
When Lucius Malfoy tries to curse Harry at the end, he mutters,"Avada..." As mentioned in the 4th book, this is the beginning of an Unforgivable Curse named Avada Kedavra, or the killing curse. This rather makes it look like Malfoy is stupid enough to actually try kill a child in the middle of a school chock-full of students and teachers with no means of escaping. But as Jason Isaacs has explained in several interviews, the novel mentions no specific spell for him to use and, since he had just been reading the 4th book at the time, this was the only curse he could remember.
In the book, the Polyjuice Potion changes a person completely, including their voice. You will note that there was no change in Mad-Eye Moody's voice in The Goblet of Fire. Harry and Ron do not have to disguise their voices when they confront Malfoy, but instead have to be careful about the way that they talk in order to sell their identities of Crabbe and Goyle, so that Malfoy doesn't suspect anything.
When Harry and Ron are under Polyjuice Potion and interrogating Malfoy, he asks Goyle (Harry), if a small wrapped gift is his, and he answers no. However, in numerous freeze frames throughout the movie, the gift can be seen in Harry's possession
In the scene which Harry speaks to Tom Riddle by writing in the diary, the handwriting seen isn't actually that of Daniel Radcliffe. Chris Columbus didn't feel that Radcliffe's handwriting was how Harry would write, so an extra's handwriting was used instead.
The filmmakers assumed that the Chamber of Secrets' only appearance would be in this film. However, the Chamber ends up making a second appearance in Harry Potter and the Deathly Hallows: Part 2 (2011). Since the set had been dismantled it had to be constructed again.
When Harry sees Sir Nicholas with his head chopped off and gets in trouble by Mr. Filch, professor McGonagall takes Harry to Dumbledore's office. When they arrive at the stairs, McGonagall says "Sherbet Lemon" to open the stairs. Sherbet Lemon is Dumbledore's favourite candy which he says in Harry Potter and the Sorcerer's Stone (2001).