sexy teen girl: See Hilary Duff's Sexy Danskin Campaign Pics

Hilary Duff at the premiere of War, Inc. at th...

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See Hilary Duff's Sexy Danskin Campaign Pics

Credit: Jordan Strauss

Duff's got the right stuff!

Hilary Duff is lacing up her sneaks and flexing her muscles in a series of new ads for Danskin.

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Part of the athletic wear brand's "Move for Change" initiative, the actress joins other hot-bodied celebs Padma Lakshmi, Jenny McCarthy and Christie Brinkley for a campaign that supports health programs for women and children.

"This Danskin campaign is for women of all ages: 20s, 30s, 40s and 50s and what they like to do to stay in shape -- physically and mentally in mind, body, and soul," Duff, 23, said in a statement.

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In the ads, the sportsbra-clad star is shown going on a hike while modeling Danskin's latest sports apparel -- and in turn showing off her great figure.

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So how does Duff -- who shot to fame on Disney Channel's Lizzie McGuire in 2001 -- stay in such great shape?

"I work with trainer Harley Pasternak and I do a lot of Pilates," she told Us Weekly in April. "I'm just like everyone else. I go through stages where I feel super motivated and want to work out every day, and then I won't work out for two or three weeks and I'll feel like s**t. Then it's time to hop back on the wagon again!"

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