Why Was Harry Potter Star Emma Watson "Nervous" Making Perks of Being a Wallflower?

Emma Watson is ready to leave Harry Potter behind.

No, she's not hating on the megasuccessful movie franchise that brought her fame and fortune, but

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She can't wait for Potter fans to see The Perks of Being a Wallflower, a coming-of-age drama that marks her first starring role post-Harry.

"I think Harry Potter fans will love it because it has so much heart, like the Harry Potter stories do," Watson, 22, told me yesterday at the MTV Movie Awards. "I feel like it's the perfect transition from Harry Potter to kind of a more adolescent movie. It's a little bit of an older tone. It's darker."

In the flick, Logan Lerman plays a shy high school freshman who is befriended by two seniors, Sam (Watson) and Patrick (Ezra Miller).

In one scene, Watson performs a dance routine from The Rocky Horror Picture Show in skimpy lingerie. "I was very nervous to that stuff," she said. "It was tough."

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She was also nervous about doing her first American accent. "I really wanted to get that right," Watson said. "But Logan and Ezra were very instructive. If I ever said anything that sounded weird, they were like, 'That's not right!' and we would fix it."

Costar Johnny Simmons said the movie might never have been made without Watson attached. "She read the book and became obsessed with it," said Simmons, 25. "She heard they were making the movie and approached them about it. We wouldn't be here if it wasn't for her."

We can't wait to see it.

Now we want to hear from you. Excited to see The Perks of Being a Wallflower? Chime in below.

PHOTOS: Emma Watson Fashion Spotlight