This post has not been vetted or endorsed by BuzzFeed's editorial staff. BuzzFeed Community is a place where anyone can create a post or quiz. Try making your own!Buzz·Posted on Jan 9, 201510 Hollywood Stars Perform Folk MusicYes, Iron Man sings Joni Mitchell.by Margaret MCommunity ContributorLinkFacebookPinterestTwitterMail 1. Robert Downey Jr. Sings "River" View this video on YouTube Via youtube.com 2. Steve Martin Performs "Love Has Come for You" View this video on YouTube Via youtube.com 3. Zooey Deschanel Sings "Unchained Melody" View this video on YouTube Via youtube.com 4. Ed Helms Plays "Little Maggie" View this video on YouTube Via youtube.com 5. Carey Mulligan & Justin Timberlake Sing "500 Miles" View this video on YouTube Via youtube.com 6. Adrian Grenier Drums to "Alone No More" View this video on YouTube Via youtube.com 7. John C. Reilly Plays "I Ain't Got No Home" View this video on YouTube Via youtube.com 8. Keira Knightley Sings "A Step You Can't Take Back" View this video on YouTube Via youtube.com 9. Hugh Laurie Performs "Louisiana Blues" View this video on YouTube Via youtube.com 10. Jason Sudeikis, Jason Bateman, Will Forte, Ed Helms Perform "Hopeless Wanderer" View this video on YouTube Via youtube.com I didn't even know those guys were in Mumford & Sons.