Jamie Bell was going through puberty at the time of filming. Some of his dialog had to be post-synched as his voice had broken. And the opening scene in which he jumps up and down on a bed to T-Rex's "Cosmic Dancer" was shot over a lengthy period of time. For the latter takes, Bell had acquired hair on his legs and had to have them shaved.
Jamie Bell took ballet and other dance classes while in secondary school, which caused him to often be ridiculed by his peers. He used some of these experiences as inspiration while playing Billy Elliot.
One of the great qualms of the entire film was whether Mrs. Wilkinson should be there in the final scene, where the older Billy Elliot performs Swan Lake. Eventually, it came down to the fact that 'Julie Walters' wasn't available for filming.
Billy Elliot's original title was 'Dancer', but when they took the film to the Cannes Film Festival, there was another film called Dancer in the Dark (2000), which won the Palmes D'Or, prompting confusion; indeed, Universal Studios called the directors, producers and writer up and congratulated them. They then realized they had to change the name and settled ('rather lamely', joked the writer) on 'Billy Elliot'.
Lee Hall, who wrote the screenplay, said in an interview: "I wrote the movie of 'Billy Elliot' when I was still a neophyte playwright. I was trying to find a way of telling my own story but in a visual way. The first image that came to my mind was a kid jumping up and down on the bed like I used to do. Once I had that bit, the whole thing about dance just came tumbling out."
In the final scene, the ballet in which Billy performs is Mathew Bourne's version of "Swan Lake" where all the Swans are played by men. Billy plays the part of the Swan, the same part he discusses with Mrs Wilkinson earlier in the film.
The musical version of the film, which hit the West End in 2005 to rave reviews and numerous awards and nominations, reportedly cost £5.5 million to make: around £3 million more than the film version. Furthermore, the Broadway production cost $18 million to make, over three times as much as the original film's budget. All three were a financial success.