Friends' star Jennifer Aniston has the look the rest of America wants.

  If you ask her -- politely, because she really, really doesn't like to talk about it -- Jennifer Aniston will confess she's sick of her hair, the sexy, just-fell-out-of-bed Friends hairdo that has become the most imitated style since Farrah Fawcett's shag and Dorothy Hamill's wedge. Even trendsetter Madonna has followed Aniston's lead, adopting those signature layers in her latest look. "Yeah, I know, everyone loves it," Aniston sighs, running a hand through her locks. "But I'm sick of it and I don't know what to do, chop it off or grow it long."

  That may be blasphemy to all the women who have rushed to copy Aniston's disheveled do, in the process helping to rocket the co-star of NBC's hit series from unknown to star-in-the-making. Building on her TV success, Aniston will also be seen in the upcoming movie She's the One from hot Brothers McMullen director Edward Burns. Aniston's unstudied insouciance is precisely what her appeal is all about. With her hair in her eyes, flirty miniskirts, and navel-bearing baby T's, the 26-year-old actress has emerged as not only the sexiest of the Friends sextet but one of Hollywood's most influential style-setters, a veritable poster child for the 20-something crowd. On camera, Rachel Green, her Friends alter-ego, may be a Bloomingdale's baby reduced to coffeehouse chic; off camera, Aniston embodies a more relaxed style. "Rachel's really a clothes-obsessed Chanel girl who will wear a leopard-print turtleneck," she says. "But I'm a one-outfit kind of girl, much more comfortable in khakis and sneakers and T-shirts."

  Still, now that she's a rising star, Aniston is feeling some pressure, she says, "to get better taste." She has begun leaving the security of her J. Crew catalog to sample Hollywood hot spots -- from the trendy American Rag for thrift shop chic to Barneys for drop-dead cool. "I'm starting to buy real shirts," she says. Her latest discovery is L.A. designer Jane Booke, who whipped up the little black number Aniston wore for her recent Letterman debut.

  The only daughter of an actor dad (soap star John Aniston) and ex-model mom (Nancy), Aniston spent her childhood as the show-business equivalent of an Army brat, bouncing from a tiny house in Sherman Oaks, California, to a Manhattan apartment. Although her parents moved easily in Hollywood circles -- Telly Savalas was her godfather -- money was usually short. The family even spent a year living with her grandmother in Athens, Greece. "I have the most amazing memories," says Aniston, whose real surname is Anistonapoulos, "a bin of oranges that sat in the living room and the cat that lived on our terrace."

  By the time she was a student at New York's High School for the Performing Arts, Aniston was in full Soho mode. "My parents used to scream at me because I only wore black and I had my cut in a modified mohawk," she laughs. "My boyfriend and I looked exactly alike." for years she carried "30 pounds more than I do now," she says. "My dad used to say I had an ass you could serve tea off of."

  Aniston's comedic personality began to emerge in high school. "I wasn't beautiful so I had to be funny," she recalls. Although she laughs about her weight now, it wasn't until she lost those extra pounds that her career took off. "It's scary," she observes, "how Hollywood treats you like this completely different person when you're then."

  Now down to a curvy but hardly anorexic 112 pounds, Aniston keeps her midriff bare-able with a low-fat diet and thrice-weekly workouts with a personal trainer. "I watch what I eat, but I don't not eat a cheeseburger," she says, "because life is no fun living on salads and fruits."

  Her skin-care routine is equally no-nonsense: Aveda cleanser, Clinique moisturizer, and a little Kiehl's eye cream.Makeup is minimal -- most days she wears nothing lipstick ("never red, though"), MAC and Stila products in earth tones to emphasize her tawny skin and cool dark shadows to bring out her blue eyes.

  Though cognizant of the role her own distinctive look has had in her success, Aniston is ambivalent about Hollywood's eternal obsession with beauty. "Too many hearts have been broken because of it," she says. Asked who she finds beautiful, she doesn't hesitate. "When I was growing up, I thought Lucille Ball and Mary Tyler Moore were it," she says.That Aniston grew up admiring those gifted and decidedly down-to-earth TV comedians of earlier eras is hardly a coincidence. For TV viewers in the nineties, Jennifer Aniston is more than a little bit it herself.