When Tom Hanks took his seat in 1999 to watch Nia Vardalos's one-woman stage show My Big Fat Greek Wedding in L.A., Vardalos was thrilled. Too bad the audience forgot she was there. "All heads were turned toward him for the first 10 lines," she says, "until he laughed."

In fact, Hanks and his actress wife, Rita Wilson, who is of Greek heritage, laughed so much that they offered to produce a film version of the semiauto-biographical act. Made for just $5 million, the romantic comedy has become the sleeper phenom of the year, building up a $53 million take over four months. Says Vardalos, 39: "It's a fairy tale."

For an unlikely Cinderella. One of four kids born to Constantine, 69, a Greek businessman who emigrated in the late '50s, and Doreen, 62, a bookkeeper, Vardalos says her background set her apart. Growing up in Winnipeg, Man., "I had more body hair than the other girls at school," she jokes.

In '88 Vardalos got her big break with Toronto's Second City comedy troupe. Transferring to the group's Chicago stage in '90, she fell in love with fellow performer Ian Gomez (The Drew Carey Show). They wed in '93. "I don't think he's seen Nia and I kiss" in Wedding, says costar John Corbett. At screenings, "Nia gives his hand a squeeze so he knows to close his eyes."

Vardalos—who lives in L.A. with Gomez, 37—is now fielding offers for more films. If success hasn't quite gone to her head, it has certainly gone to her hair. "I put blonde in it just for fun," she says. "I'm a boob job away from going L.A."