Jonathan Rhys Meyers and Ewan McGregor sang their own songs in the movie. (Some of Rhys Meyers's songs were overdubbed by Radiohead lead singer Thom Yorke.)
The film was originally supposed to feature some of David Bowie's music, hence the title, which was a Bowie song from the 1970s; however, when Bowie learned that the script for the film was partially based on the unauthorized biographies "Stardust: The David Bowie Story" written by Henry Edwards and Tony Zanetta and "Backstage Passes" written by Bowie's ex-wife Angie Bowie, he threatened the producers with a lawsuit. Bowie's songs were, therefore, not used, and the script was partially re-written to avoid unnecessary resemblance between Bowie and the Bowie-style character Brian Slade.
During the Festival sequence where Brian sees Curt perform for the first time, Ewan McGregor was only due to moon the disgruntled crowd. But inspired by the antics of Iggy Pop, he improvised, and ended up gesticulating wildly while flashing the audience, leaping about with his trousers around his ankles.
Courtney Love considered supplying music to the film's soundtrack; however, she withdrew after viewing a rough cut, claiming that the character of Curt Wild too closely resembled her late husband Kurt Cobain, both in character and physicality. The Wild/Cobain parallel later became a much-discussed point among critics, and while director Todd Haynes and actor Ewan McGregor have noted similarities between Cobain and Wild, both claim the resemblance was unintended. Haynes, for his part, notes that Cobain borrowed many style traits from Iggy Pop, who served as partial basis for the Wild character.