Sexy! Jennifer Lawrence Flaunts Major Cleavage in Glamour Magazine

 Alexei Hay/Glamour

Jennifer Lawrence sure looks good in a jumpsuit.

The 21-year-old shows off major cleavage in a plunging Yves Saint Laurent ensemble for the March issue of Glamour. Despite her flawless physique, Lawrence admits she's addicted to the gym.

"I hate saying, 'I like exercising.' I want to punch people who say that in the face," Lawrence laughs. "But it's nice being in shape for a movie, because they basically do it all for you. It's like, 'Here's your trainer. This is what you can eat.'"

Jennifer Lawrence Glamour

The Louisville, Kentucky native doesn't count calories, however. "I don't diet," she admits. "I do exercise! But I don't diet. You can't work when you're hungry, you know?"

Lawrence, 21, famously beat hundreds of young actresses vying for the role of heroine Katniss Everdeen in The Hunger Games, but she didn't accept the part right away.

VIDEO: Jennifer Lawrence sacrifices herself in The Hunger Games trailer

"I gave myself three days. I knew from reading the books that I loved The Hunger Games. I just didn't know if it was worth changing my life for," she tells Glamour. "I'm at a peaceful place right now. The people who used to ignore me at parties, now they're nice to me and kissing my ass."

"I wanted to make sure that when I said yes, I wouldn't regret it. And I don't regret it," Lawrence explains. "I would have said no because I was scared, and then I would have been that bitter actress telling my grandkids, 'I'm the one that turned it down.'"

Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!

Want stories like these delivered straight to your phone? Download the Us Weekly iPhone app now!