Hewitt relished her vampish social climbing role

"I've been in the magazines for a long time now, and to be honest, if I suddenly wasn't in the magazine anymore, I'd wonder what was wrong," the 26-year-old actress says. "They feed on (an actor's) existence on the business level."

In the made-for-cable movie "Confessions of a Sociopathic Social Climber," airing 8 p.m., EST Saturday on Oxygen, the former girl-next-door on "Party of Five" is giving into her naughty side.

She plays self-involved Kayta Livingston, a shallow advertising executive who will do anything to get invited to the social event of the season. Kayta sleeps with her ex-boyfriend when she thinks he's on the list.

Kayta walks over the little people and stabs peers in the back. She even takes social climbing literally by scaling a wall to get into one event.

"I loved it," Hewitt says with a laugh as she talks of playing the vamp. "I found it really invigorating and different and fun and very much like myself when I'm PMS-ing, so it wasn't that far from who I am."

And "Climber," which was shot in 17 days, provided Hewitt a chance to shed the good-girl image she's had most of her career. The shark-like Kayta prances around in designer clothes and coos over the latest in well-heeled pumps.

It also allowed Hewitt's best buddy, Joseph Lawrence, a role he's never done before either: that of an earring-wearing, finger-snapping gay sidekick.

"This was a project that I think for all of us was a really great way to sort of play (types) that (we) don't normally get to play," says Hewitt. "I was a monster every day and was applauded for it ... and I couldn't stand myself at the end of the day playing this character most of the time."

Playing against type doesn't mean Hewitt can't relate to those social climbing instincts. She is an actress, after all, and was among the beauties on Stuff magazine's "102 Sexiest Women in the World" list. She makes sure she's at the right place at the right time to get publicity.

"I think that's all part of the business of being an actor and surviving in this town where there's thousands of really beautiful, really talented people," says Hewitt, a Texas native.

"A select few get to be the ones in the magazines and talked about and stuff like that. I absolutely think there's a parallel as far as that goes."

Of course the photographers who hound her don't always catch her on a good day, like the time she exited a workout so she could go to Taco Bell. "I try to be so good with my junk food," she says, "and they catch me on the one day (of weakness)."

Social climbing has also affected her personal relationships. Until recently, she says her closest friends have been male because of the cattiness among actresses in Hollywood.

"When you're young, especially in the entertainment industry where it is so competitive, it can be hard to have female friends," she says.

Those kinds of things concern her more than how she might be perceived for doing a basic cable movie. The star of "I Know What You Did Last Summer" and its sequel says Oxygen gave her the freedom to do something different. (Her next major TV role will be as a medium on a network drama set for next fall.) A feature film might not allow her the opportunity to go against type so easily, she says. Cable is more experimental in that way for actors.

"Because it's on Oxygen ... I get to do sort of all these fun, fantastic and wild things that I wouldn't have been brave enough to do in real life," Hewitt says. "I think that's what's fun in playing it. Women are really enjoying the powerful, sexy, kind of great attitude-filled girl right now on TV."