Justin Timberlake doesn't limit his musical collaboration to rappers: he's revealed that he recently spent some time in the studio with  Marcus Mumford , frontman for the Grammy-winning folk-rock band Mumford & Sons   The two teamed up to create music that will be featured Justin's upcoming film, Inside Llewyn Davis .

"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," Justin told the U.K.'s Capital FM . "So not only will that be a great movie, but the music to it will be fantastic.”

As for why Marcus and JT hooked up to begin with, one of the stars of Inside Llewyn Davis is actress Carey Mulligan , Marcus's wife.  The film, directed by the Coen Brothers , is about a singer-songwriter in the New York City folk music scene of the 1960s. In addition to JT and Carey Mulligan, the movie also stars Oscar Isaac , Garrett Hedlund and longtime Coen Brothers staple John Goodman .

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