Who knew that Keira Knightley can sing? In her new film 'Begin Again' co-starring Adam Levine and Mark Ruffalo, Knightley reveals a Norah Jones-esque voice as an amateur singer-songwriter. When all three stars sat down with AOL.com's Brian Balthazar, Ruffalo revealed a fascinating scenario. If nominated, Knightley could perform at the Academy Awards. 'Begin Again' is in theaters nationwide now.