PASADENA, Calif. — Apparently, if you agree to appear on an MTV "reality" show and then you sleep around, act like a witch and become one of TV's most infamous spoiled-brat teens, it's a smart career move.

Kristin Cavallari, who was the-girl-you-loved-to-hate on "Laguna Beach," has parlayed her infamy into a gig hosting UPN's feel-good "reality" show "Get This Party Started."

The producers "saw me on 'Laguna Beach,' and I came in and auditioned," Cavallari said.

How, exactly, what she did on "Laguna Beach" qualified Cavallari to host a show that's all about rewarding nice, deserving people, the producers couldn't say. Even Cavallari said she was surprised.

"I'm shocked. It's really unbelievable," Cavallari said. "But I'm having the best time."

In tonight's premiere of "Get This Party Started" (8 p.m., Ch. 24), a young woman whose life was seriously disrupted by Hurricane Katrina is taken to Las Vegas, where the show (conspiring with her sister) tells her she's been selected for a talent competition, buys her new clothes, gives her a makeover — and eventually throws her a huge surprise birthday party. Cavallari and Ethan Erickson co-host; special events coordinator Lara Shriftman and her team do the heavy lifting.

It's sort of the nice twin to "My Super Sweet 16," the MTV show about spoiled brats whose indulgent parents throw them obscenely expensive, grotesquely overblown parties.

" 'Laguna Beach' was completely different than 'Get This Party Started.' This one has a completely different concept," Cavallari said. "It's a lot better."

When that comment elicited laughter she didn't expect, Cavallari changed her story.

"Sorry. Sorry," she stammered. "I don't mean it's better. I just mean it's . . . I mean, it's more of . . . this is more of a feel-good show rather than a high school drama."

Given that "Laguna Beach" launched her on a career that, to this point, has included a guest shot on "Veronica Mars," an appearance in a Teddy Geiger music video and "Party," it is not surprising that Cavallari has no regrets about being that girl-you-loved-to-hate.

"I don't regret anything. And it's only helped me," she said. "And I'm so happy. I mean, with 'Laguna Beach,' now I have my junior and senior years of high school on tape for the rest of my life. And that's priceless."

Maybe someday Cavallari will be less enthusiastic about having a filmed record of cheating on her boyfriend, sleeping around and backstabbing classmates. But not today.

For now, she's just basking in the glow of her MTV fame. She relishes having people recognize her in public.