Sarah Michelle Gellar

Sarah Michelle Gellar is best known for kicking the hell - literally - out of the forces of evil in the TV series "Buffy the Vampire Slayer." However, in her new film, "The Air I Breathe," her character does something much more challenging, or at least harder to get a handle on: She tries to become a whole person.

"The idea is that until you’ve known great sorrow, you can’t really understand great happiness and pleasure," says Gellar, who speaks at native-New Yorker-speed. "Until you’ve known great happiness and pleasure, you don’t really know how to get through those deep, sorrowful moments. That’s what makes us who we are."

Director and co-writer Jieho Lee compares the film to a sort of hard-boiled "Wizard of Oz," with Gellar’s character, named Sorrow, as a kind of Dorothy Gale stand-in. In fact, it’s inspired by a Chinese proverb that separates life into Happiness, Pleasure, Sorrow and Love, each represented in the film by characters whose paths cross: Forest Whitaker plays a banker who runs into trouble with a gangster; Brendan Fraser is the gangster’s muscle, who is supposed to shake down the banker and keep tabs on a pop star; Gellar is the pop star, who has an affair with him; and Kevin Bacon is a doctor who needs the pop star to save the life of an old love (Julie Delpy).

"I always looked at it as if the whole story was [about] one person, and we made up the individual facets that make up a person," Gellar says.

Gellar was the first member of this solid cast to sign on. She responded not only to the film’s themes but to her character. Some of what the pop star is going through is uncomfortably familiar to her - including a scene in which she has a meltdown in public after being mauled by fans.

"I’ve certainly had those experiences where you’re still a little female, and even though you know you’re not in danger it’s still hard to have those cameras in your face," Gellar says. "It’s hard to have these people jostling for a position around you. You still feel vulnerable, and that’s what I think I can bring to that situation."

There’s also a scene in which her character is put in the hot seat by a hostile interviewer. She looks like a deer caught in the headlights.

"I haven’t had an interview go as south as she did," Gellar says, "but I’ve had interviews where you know it’s not going the way it’s supposed to. It’s a weird dance that we do: You have a very brief time to get people to get a feel for who you are, and there are plenty of people who have their own opinions, and that’s difficult. That’s my own version of what she’s been through."

Gellar, now 30, knows what she’s talking about. She has been in the business most of her life, first as a child model (for Burger King), then as a teen actress (winning a Daytime Emmy for "All My Children"), and finally achieving real stardom in "Buffy." She has been a staple of men’s magazines, hot lists and Hollywood beauty polls. Her film career includes horror pics ("I Know What You Did Last Summer," "The Grudge," "The Return"), indie films ("Southland Tales"), winking pop-culture riffs (a blond slasher-film coed in "Scream 2," Daphne in the two "Scooby-Doo" films) and family films ("Happily N’Ever After," "TMNT").

Now finally free of Buffydom, she laughingly says her last three roles have been "a porn star, a pop star and a lawyer." Offscreen she has become an ambassador for CARE, hobnobbing with such pols as Hillary Clinton (at the end of the month she’ll be going to Africa).

"The fortunate thing is for the first time in my life I have time," says Gellar, who is married to actor Freddie Prinze Jr. and recently changed her name to Sarah Michelle Prinze (she’ll continue to use "Gellar" professionally, however).

"When you’re on a television show for eight years, your projects are picked by what shoots on my hiatus," she says. "Now I can do a project and take four months off. I can pursue outside interests. It’s just sort of finding what that balance is."