Portia, Portia, Portia!

Encircling the middle finger of Portia de Rossi's right hand is a thin, dark line. To play the serious yet stylish attorney Nelle Porter on Fox's Ally McBeal (Mondays, 9 P.M./ET), the actress hides her tattoo with a ring. A discreet symbol of rebellion, it's just the right touch for a woman who is razor sharp and a tad edgy. "I thought about what would best suit my lifestyle," she says. "This [tattoo] is perfect."

Brains and bravado: de Rossi, 25, has both. "She's very intelligent and that comes across in her acting," says Ally creator David E. Kelley. "Yet there is something mysterious about her as well." Not unlike Nelle, the boat-rocking character who joined Cage/ Fish &Associates this season. She's smart and so icy she can freeze the competition with a smile (hence the nick-name Sub-zero), the antithesis of neurotic Ally (Calista Flockhart). So far, Nelle has set her sights on loopy John "The Biscuit" Cage (Peter MacNicol). "She's definitely drawn to him," says de Rossi. "But you know the Biscuit; he's going to have a few problems. Of course, Nelle is going to keep trying."

Staying focused is a trait de Rossi shares with Nelle. So much so, in fact, that as a girl in Melbourne, Australia, she maintained A's at an exclusive grammar school and a busy modeling career that started at age 11. So focused that at 18 she got into the prestigious University of Melbourne to study law-and a year later landed a role in the 1994 film "Sirens" despite her lack of acting experience.

"I had no intention of being an actress," de Rossi says over salad at a restaurant near her rented house in Santa Monica, California. "I really didn't. I worked very hard to get into law school." She tried out for "Sirens" on a lark, hoping to meet idol Sam Neill, one of the stars. "But because I'm used to working hard at everything, I really worked hard at the audition." For lunch, de Rossi is dressed in black, her platinum locks plaited into a demure braid. In fact, that hair is a big part of her character; during work, Nelle wears a tight bun, only to let it loose to mesmerizing effect.

De Rossi grew up Amanda Rogers, one of two children raised by a single mom, Margaret, a medical receptionist (de Rossi's father died when she was 9). Lithe and poised, by 14 she had a booming career in TV commercials. She was also savvy enough to know that a new name-a fabulous name-would give her a leg up. Goodbye Amanda, hello Portia. "I just made it up.… I liked it better," she says, blushing a bit. "It was the most courageous thing I've ever done."

Her decision to move stateside was equally bold. In 1994, at the Denver airport on her way home from the Telluride Film Festival, she switched her ticket from Sydney to Los Angeles. "It took five or six hours of deliberation," she recalls. "But I figured I had this great opportunity and it would be foolish not to see where it led."

She also decided to jettison her accent. "I'm afraid I sound like Paul Hogan every time I try [it] now, it's so exaggerated." She does, however, retain her dry-as-the-outback Aussie sense of humor. Like Nelle, de Rossi often finds herself saying "just kidding" to Americans who don't get it.

These days, she's basking in the limelight, even choosing a sidewalk table at lunch. Doesn't she worry about being recognized? Nope. "Bring it on!" she says. At the Emmys, she donned a stunning Valentino gown and vamped for photographers. "I couldn't stop my head from whipping around," she says. "Living in Australia, the idea of being that close to major stars is a complete fantasy."

De Rossi met Kelley a few years before Ally McBeal when she read for a comedy pilot of his that wasn't picked up (problems with her work visa kept her from getting the role). "I always remembered her," says Kelley. "So," de Rossi says, "he told me I owed him a show." Before Ally, she was probably best known for 1997's "Scream 2," in which she plays a sorority girl who gushes to Neve Campbell, "Hi. No, I really mean that. Hi." ("That line will [haunt me] for the rest of my life," de Rossi says.) Other credits include Fox's short-lived comedy Too Something and the WB's Nick Freno: Licensed Teacher.