Once is a 2007 Irish musical film written and directed by John Carney. Set in Dublin, this naturalistic drama stars musicians Glen Hansard (of popular Irish rock band The Frames) and Markéta Irglová as struggling musicians. Collaborators prior to making the film, Hansard and Irglová composed and performed all but one of the original songs in the movie.

Shot for only €130,000 ($160,000), the film was very successful, earning substantial per-screen box office averages in the United States. It received extremely enthusiastic reviews and awards such as the 2007 Independent Spirit Award for best foreign film. Hansard and Irglová's song "Falling Slowly" received a 2007 Academy Award for Best Original Song and the soundtrack as a whole also received a Grammy nomination.