Evangeline Lilly, who plays Kate, the handcuffed fugitive turned alluring castaway on ABC's Lost, knows something about surviving in the wild. At 18, as a missionary in the Philippines, she lived in a grass hut, climbed trees and bathed in a river under the watchful eye of tribal members. "They thought that a crocodile was going to jump out and get me," says the Canadian-born actress, laughing. "I just didn't think so."

Lilly, 25, brings that same bravado to Lost's mysterious island. "She has a very confident way about her," says executive producer J.J. Abrams (Alias). Plus, "she's beautiful and she's got a great smile, a little goofy."

All the better to conceal some major anxieties. When she got cast in Lost last spring, the former Ford model had only one notable acting credit, a bit part in Stephen King's Kingdom Hospital. "There was pressure," she says. "I was supposed to become a star." She was also supposed to do a nude bathing scene but refused—"I'm a prude, OK?" Costar Matthew Fox made her feel at home. "He's like a big brother," she says. "He took me under his wing."

At her rented three-bedroom bungalow on Oahu, where Lost is filmed, "I feel really at peace," says Lilly, who calls herself "single and unavailable. I don't know where you find the time for a relationship with a job like this." Still, "I get paid to work on the beach. This is my office. I've got no complaints." And so far, no crocodiles creeping up on her.