For as beautiful and ethereal as the world of ballet appears to be, whether via live performance or in movies, Darren Aronofsky and Natalie Portman have gone to great lengths to shatter that pristine exterior in their new film, "Black Swan," which arrives in theaters Friday. When MTV News caught up with Portman, we asked her what she went through in order to get into her character's dark and disturbing world.

"It was really extreme," Portman said of her physical commitment to the role. "And I definitely felt both physical and mental aftershocks from the experience, because it was the first thing I've ever done that was this physically demanding on top of an emotionally demanding part," she said. "And it's great. I mean, the kind of discipline that it demands also puts you in that space for the acting part. But yeah, it affects you in ways. I'll probably figure out how it affected me in, like, five years. I'll look back and go, 'Oh, that's why I did that and that and that.' "

Portman also said that, although she and Aronofsky first discussed the project nearly a decade ago, she needed more age and experience to tap into certain aspects of her character.

"For me, it's really about someone going from a position, an artistry where you're trying to please other people, to a position where you're finding pleasure yourself," she said. "And Vincent [Cassel]'s character, though it seems that he's sort of puppeteering this character, he is really guiding her towards becoming an artist and is really teaching her how to find her own pleasure and make a true expression of herself, that it's about her."

The 29-year-old went on to say that she related to her character finally realizing that it's not her job to make others happy. "It's about breaking out of a system where you're easily replaceable by the next girl who looks like you. And I feel like my 20s were about that, and probably into my future, I'm sure it'll continue being that way," Portman said. "But the older you get, the less you care about what other people think and the more you just want to be your true self and express your true self."

Check out everything we've got on "Black Swan."

For breaking news, celebrity columns, humor and more -- updated around the clock -- visit MTVMoviesBlog.com.