In a recent interview with Playbill magazine, when asked if she had any aspirations to star in a Broadway musical, she said, "No. I don't think I've got a voice that would do a musical. I don't think I do, so no. I don't think so. I mean, I think that's so fun, and I love singing along to them, and I love seeing them, but no. I don't think that I could pull that one off."

Knightley sang in "Begin Again," playing Gretta James, a songwriter who has just broken up with her boyfriend and writing partner, Dave Kohl (Adam Levine), and goes on to sign with record label executive Dan Mulligan (Ruffalo).

The song "Lost Stars," performed by Knightley for the film, was nominated for an Academy Award for Best Original Song.

Watch it below:

John Carney, the writer-director of "Once" (the film that inspired the Tony-winning musical of the same name), also wrote and directed "Begin Again."

Although Knightley says no to a future in Broadway musicals, she's excited to hit the Great White Way in Thérèse Raquin and said that theatre has always been her dream.

What attracted her to theatre? "I mean, that's what I wanted to do. My mom is a playwright, my dad was a theatre actor. I grew up going to their rehearsal rooms, and I grew up going to a lot of theatre," she said. "The way of things, because acting isn't necessarily a job that you can really plan, I just happened to get film and television work, and I didn't happen to do any theatre. And then, once you're on that road, you just keep going and keep going and keep going.

"I think I did my first play when I was 24 [The Misanthrope in the West End], and it was only after my dad turned around and went, 'You do realize that you haven't actually done what you always planned to do, and when are you going to do it?' And, I do. I love it. I love the whole process of creating the character and the story, and the rehearsal room is a really magical place. And live performance — there isn't anything like live performance because it changes every night. You're not seeing something that's dead that is simply being replayed; you're seeing something that is very much alive and very much changing with the character of the audience who come in. The audience is another character in the play, and you never know what personality they're going to have, so it does alter it, and that's a really fun thing and an exciting thing to play with."

She begins performances at Studio 54 Oct. 1.