Justin Timberlake and Mumford & Sons frontman MARCUS Mumford have joined forces on a track for the Coen Brothers' new movie.

Timberlake appears in the film, Inside Llewyn Davis, alongside Mumford's wife Carey Mulligan.

The pop star tells U.K. radio station Capital Fm, "Marcus and myself, we all kind of worked on the music together and I don't know any other world where we would have the opportunity to collaborate like that but it was so much fun."

The new Coen Brothers film is loosely based on the life of 1960s folk icon Dave Van Ronk.

Timberlake plays Mulligan's husband, Jim Berkey, in the movie.