He may do Stoppard on Broadway. May have studied the Bard at Yale School of Drama. May come from an impressively cerebral family. But to most of America, Paul Giamatti will be known simply as Pig Vomit. And that's okay. ''Yeah, I'm classically trained, but I'm not really very good at it,'' laughs the actor as he sips tea in his Manhattan loft. ''And anyway, there's a Shakespearean quality to Pig Vomit -- he's kind of in the evil Iago mold.''

Evil indeed. For those unfamiliar with the gospel according to Howard Stern, Pig Vomit is Stern's nickname for Kenny, the dastardly WNBC exec in Private Parts who tries to censor the shock jock's pubescent rants. (In reality, Stern called his nemesis Pig Virus, but the name was changed because the on-screen villain is a composite.) It will surely be a breakout part for Giamatti, who plays the character to a twangy, sputtering, tantrum-throwing T. ''He's got that soft face, those rat eyes,'' gushes the film's director, Betty Thomas. ''He's the perfect sleazy guy!''

Costarring opposite Fartman is a curious fate for a guy who once planned to follow in the academic footsteps of his father, A. Bartlett Giamatti, the late English professor and Yale president also renowned as Major League Baseball's commissioner in the late '80s. ''I always thought acting was a goofy thing to do for a living,'' says Paul. ''Sometimes I still do.''

But Giamatti, 29, got hooked on theater as a Yale undergrad, bouncing between regional and legit stages (he's currently in Three Sisters on Broadway, with Amy Irving, Jeanne Tripplehorn, and Lili Taylor), and tiny screen parts (a homeless guy in NYPD Blue, a G-man in Donnie Brasco). When the porcine call came, though, he was ready for his long shot, Mr. DeMille. Says Thomas, who auditioned Giamatti's Southern-fried shtick three times before casting him, ''I made him work his ass off.''