One of the biggest challenges that Elton John faced in trying to get this project moving forward is that many producers told him they wanted to make a PG-13 rated film. John told them all the same thing: that he had not led a PG-13 life.
The exterior footage of early 1970s LA during the Troubadour club era was stock 35 mm footage that was digitally cleaned up as it would have been far too impractical and expensive to redecorate parts of Sunset Boulevard in a 1970s style just for the few seconds of film required.
When Elton calls his mother to tell her he's gay, she and Fred are watching Liberace on television. Liberace was a flamboyant piano player whose homosexuality was widely suspected but never publicly acknowledged during his lifetime.
Dick James (played in the film by Stephen Graham) was an interesting man in his own right. Prior to setting up the DJM record label in the late 1960s (which published Elton's early records) he had made his name as a session singer, most famously singing the theme tune to the Richard Greene television series The Adventures of Robin Hood (1955). In the early 1960s he ventured into music publishing and was a co-creator (along with Brian Epstein) of 'Northern Songs Ltd' to deal with publishing rights for songs penned by The Beatles. After the death of Epstein in 1967 his relationship with the fab four deteriorated and he sold his share of Northern Songs to Sir Lew Grade's ATV company at a handsome profit, and without consulting John Lennon & Paul McCartney (as they were under the impression there was an agreement that any sale of James's stake in the company would be offered to them first). DJM were Elton's UK record label until 1976 (US sales were licensed by DJM to RCA) when he started publishing under his own 'Rocket' label brand that he had started in 1973 to handle other artists. One of the earliest Rocket artists Elton signed up was Kiki Dee. In the 1980s John took legal action against James over rights issues and won his case shortly before James died in 1986 aged 65. After his death the rights to the DJM back catalog (minus Elton's records) were sold to Polygram.
In any early scene a music producer tells Elton he's going to shoot the next piano player who plays Streets of Laredo. This is potentially a nod to Elton John's album "Don't Shoot Me I'm Only the Piano Player".
The trivia items below may give away important plot points.
Elton's suicide attempt is portrayed as the inspiration for the song Rocket Man. It was actually inspired by actual NASA scientists. An earlier suicide attempt, in which Elton stuck his head in an oven but was rescued by Long John Baldry, inspired the song "Someone Saved My Life Tonight."
In the film, Elton mentions that his full name is Elton Hercules John. The film makes out that he chose John as a surname while looking at a picture of the Beatles (featuring John Lennon), but in reality he chose John because he was a fan of singer Long John Baldry. The Hercules part of the name came later and he decided upon it whilst watching the British TV series 'Steptoe & Son'", where the name of the Steptoe's horse was 'Hercules'.