Merchant-Ivory's glamorous new ingenue never dated Ken Branagh. She's not even British. She lives with her parents on the Upper West Side and shares a room with her brother.

BY VANESSA GRIGORIADIS

"I don't really like boys my age," says actress Leelee Sobieski. "Plus, they're not interested in me 'cause I'm too tall." The five-foot-nine-inch, 16-year-old actress takes a sip of water from a crystal goblet. "Leo is okay -- he needs to build up his stomach a bit. But the guys I find really fascinating are about 70 years old."

As it happens, the candlelit porch of Southampton's SagPond Vineyard is crawling with such . . . guys. Arthur Miller, for one, is nearby chatting with E. L. Doctorow. Salman Rushdie is kissing William Styron hello. And there in the corner, Norman Mailer, jolly and all dressed up, is negotiating a stair with his wooden cane. All are here to celebrate Sobieski's new film, Merchant-Ivory's A Soldier's Daughter Never Cries. "This," says the actress, who spent dinner discussing extinct birds with Peter Matthiessen, "is the most fun I've had in ages."

Hollywood's new favorite ingenue was discovered by Woody Allen's casting director in the cafeteria of the Trevor Day School, on the Upper East Side, in 1994, and since then has acted in five films, including Jungle 2 Jungle and Deep Impact, and has two more in the can: Never Been Kissed, opposite Drew Barrymore, and Stanley Kubrick's Eyes Wide Shut, with Tom Cruise and Nicole Kidman. "It's hard, because a lot of my old friends from school are wondering, 'Why can't I be a movie star too?' " says Sobieski solemnly. "So now I'm only close with my close, close friends."

Ismail Merchant, the producer of A Soldier's Daughter, breaks away from a conversation with Betty Friedan to ruminate on his new leading lady's charms. "Leelee is childlike, yet she has the appeal of Ingrid Bergman," he says, sipping from a flute of champagne. "She has no technique, but rather a spontaneity in her work that comes from the inside." The film, directed by James Ivory, is based on the book by Kaylie Jones, and is a thinly veiled account of life with her famous father, the World War II novelist James Jones. After auditioning more than 500 girls in Europe and America, Merchant and Ivory decided on Sobieski over coffee at L.A.'s Peninsula Hotel. But there was one more hurdle she had to clear before being awarded the part. "I wanted to know how much pain she's had in her life," explains Jones. So the two met for tea at Sarabeth's Kitchen. "And, you know," says Jones, "she hasn't had any."

Raised on the Upper West Side by fiercely protective parents, Jean and Elizabeth Sobieski, Leelee -- whose real name is Liliane -- still shares a room with her younger brother in the rent-stabilized apartment her mother moved into during college. Her freelance-writer mom and painter dad introduced Leelee to Shakespeare in the Park when she was 3, took her on the SoHo art-gallery circuit every weekend, and refused to let her watch more than one hour of television per week. There were flamenco lessons at Ballet Hispanico, riding at the Claremont Stables, and oil painting alongside her father's easel at his studio in the West 100s. "Back then," she says without a hint of irony, "I wanted to be a painter, a director, a writer, an architect, a poet, a potter, a dress designer, an illustrator of children's stories, or an interior designer." She flips her tawny mane over a shoulder. "But I like it. Fame. I do. Now I want to be a star."

With a bright smile, chubby cheeks, and long, long hair and legs, Sobieski is the perfect ratio of girl to woman for studios hungry for the next Liv Tyler, Claire Danes, or Christina Ricci -- intelligent, sexy ingenues who seem to have been plucked straight out of A.P. comp-lit classes.

"This is not a girl," declares Drew Barrymore, whom Sobieski calls her idol. "This is absolutely a woman. A beautiful, stunningly smart, amazingly cool young woman. A wise flower."

Sobieski admits that she's kissed more boys onscreen than off. Ivory confessed to being so bothered by directing her make-out scenes in A Soldier's Daughter that he delegated it to an underling. And she has a discomfiting habit of asking the men she's worked with for a lock of hair as a memento -- even Kubrick and Ivory, neither of whom has much left. "That's just part of the fun," she giggles.

At times, it's hard not to think of the title character in a certain novel -- one that her parents don't want her to read for a couple more years. "It's just creepy for her to have a familiarity with Lolita this young," insists her mother, who also discouraged her from auditioning for the part in Adrian Lyne's remake.

On the last day of shooting Eyes Wide Shut, Sobieski gave Tom Cruise a good-bye kiss. "Just a little peck. His 4-year-old girl looked at me, like 'What are you doing, you're not my mommy!' And I wanted to say, 'Don't worry, I'm just a kid too.' "

On a bright September day a week after the premiere, Leelee is enjoying an unchaperoned walk down Broadway. She's wearing pegged jeans, an orange V-neck T-shirt, and black Nine West sandals that she bought in such a hurry she forgot to take off the shoe-store peds. After a trip to the toy store for some little plastic bugs that she plans to glue on barrettes -- "Everyone puts butterflies in their hair; I want cockroaches" -- I suggest a stop at Barnes & Noble. Her eyes get very wide. "Ooooh, my mother doesn't like me to go in there 'cause they shut down our neighborhood place, Shakespeare & Co.," she says. "We like to go to bookstores where the clerks have read the books." She looks up and down Broadway warily. "I guess it's okay, as long as we don't buy anything."

We sit down at the Starbucks inside the bookstore, but suddenly she stands up. "I don't like it here," she says. "The atmosphere is bad." After a stop at a pay phone on 86th Street -- Sobieski house rules dictate that she must call her mom every hour -- we decide on frozen lemonades at Popover Cafe on Amsterdam Avenue. "Ooooh, don't tell my papa we went here," she says. "He just thinks it's really inauthentic, that the lighting's too harsh, the air-conditioning's too strong, and everyone really hates each other but they're pretending to be nice."

After choosing two worn teddy bears from the café's display window to join our tea party, Leelee picks at her half of a popover. "I used to be one of those lucky people who could just eat and eat and eat and nothing would happen to me, but after I became a woman, so to speak, that completely changed," she says. "Not that I'm saying I'm a real woman. That doesn't happen till you're at least 25."