As Hayden Panettiere walks a deserted strip in Hollywood, the 19-year-old star of NBC's Heroes glances around nervously, occasionally spinning her head to check behind her. Wearing short denim shorts and brown UGGs and toting a big bag, the diminutive actress looks like an elfin princess on the run. "Hello," she says, walking into a little vegan restaurant, greeting me as she shrugs off her load. She orders a bowl of brothy vegetable soup and twirls her little gold whale-tail necklace, a symbol, she explains, of her devotion to the cetacean cause. The petite, bronzed blonde keeps looking out the window, over her shoulder. Not surprisingly she's afraid she's been followed—Panettiere has become the ultimate tabloid chum.

She has lived her whole life in the public eye. "I started doing this, and I know it sounds absurd, but 11 months old, I did my first commercial." The daughter of an actress and a New York City firefighter, Panettiere spent her childhood bouncing between 30-second spots and roles on One Life to Live and Guiding Light. "I remember hearing in first grade, 'Oh, why does she get to skip school?'" she says. "It wasn't like I suddenly started feeling different. I always knew that I was. I never felt I missed out—in fact, it was like, 'Oh, thank God I'm not that.'" Namely, she means, a regular kid.

It's not easy being beautiful and special and talented, and Panettiere lived through her share of Mean Girls shit. Mostly homeschooled, she occasionally returned from acting gigs to her public school in Rockland County, New York, and her classmates' wrath. In middle school, she was punched in the face by "a very angry, very sad girl," she says, as if echoing the words her mom used to comfort her at the time. "I was tortured, emotionally tortured by these girls. Every time I came back from filming, it would be me trying to find my way back into the clique. And they weren't having it."

Panettiere seems to have emerged victorious from her teen trials. After a series of minor TV and movie roles, she was cast at age 16 as Heroes' invincible cheerleader, Claire, and quickly blossomed into the queen of high-school geeks of all ages. (Her new teen comedy, I Love You, Beth Cooper, is about a nerd who falls for the hottest, most popular girl in school—notice a trend?) When she was 18, photos began appearing of her with her then-30-year-old costar, Milo Ventimiglia—piggyback rides, cuddling, shopping excursions. The two steadfastly denied any romance, but the tabloids feasted. "When it comes to relationships, it's nice to have something that is your own and not everyone else's," she says. "That's not part of my job. I never stood up on a podium and said, 'Vote for me—I'm perfect. I'll be this for you and never do anything wrong.'"