Beware! Eighteen-year-old Uma Thurman is entering the room entirely too early in the morning. "I haven't slept all night, and three cups of coffee have me frantic. Usually I'm moody and snappy when I don't get sleep," she says, tossing back her long blond hair. "S—happens." As Cécile, the voluptuous, 15-year-old virgin deflowered by reptilian roué John Malkovich in Dangerous Liaisons, newcomer Thurman is receiving lots of accolades—and lots of exposure. In fact, in the film version of Christopher Hampton's hit play, Les Liaisons Dangereuses (based on Choderlos de Laclos' 18th-century novel), her heaving bosoms get laughs. Ask Thurman about baring her breasts in the French bedroom drama—and stand back. "This film is not about my t---. Excuse my crass language, but what do people want from me, a still?" she says. "I didn't get emotional problems doing it. I haven't found myself on the subway pulling off my blouse or in a restaurant suddenly tearing my pants off."

Obviously, this Uma may be young, but she's pretty outspoken and self-assured. "She's 18 going on 40. She's far more worldly than I am," says Liaisons director Stephen Frears. "There is nothing twitchy teenager-ish about her," agrees co-star Malkovich. "I haven't met anyone like her at that age. Her intelligence and poise stand out. But there's something else. She's more than a little haunted."

Blame it on a spirited childhood. Her father, Robert, a religion professor at Columbia University, named her Uma after a goddess in Hindu mythology. The Thurmans—her father, mother Nena and three brothers—led an itinerant life. Uma was born in Boston, where her father was a grad student at Harvard. Sabbaticals were spent in Europe and India. Says Thurman: "I didn't completely belong at any of the schools I went to. I had a funny name, a funny face, big nose, and people told me I was more ugly than pretty." Uma developed a tough, independent personality. At 15, she left Woodstock, N.Y., where her family was living, to pursue acting in Manhattan. She supported herself by modeling and washing dishes.

No more. Next she'll be seen as Venus in Terry Gilliam's comedy The Adventures of Baron Munchausen, due out in March. Her offscreen romances may not be as heated as her onscreen romps. Does she have a beau? "What? Do you think I'm a lesbian?" she barks. Pressed, she says, "I'm a neuter. I'm not dating anybody now. I like my jade plant, Henry." Any other questions?