On Broadway: newcomers, perhaps, but the Grease reality show winners aren't novices.

Practice, practice, practice.

That was the ultimate message of You're the One That I Want, the 12-week exercise in hyped-up television that resulted in the casting of Laura Osnes and Max Grumm as Sandy and Danny in the new Broadway production of Grease. Like American Idol and Dancing With the Stars, Grease: You're the One That I Want was meant to tell a Cinderella story, with the viewers in the role of fairy godmother. But Osnes and Crumm, who first won spots among the 14 finalists competing on the live NBC broadcast and then came out on top in the audience voting, have both been doing musical theater--practicing, practicing, practicing--since childhood. Cinderella had nothing to do with it.

Osnes, whose wholesome charm earned her the nickname "Smalltown Sandy" on the broadcast, says, "I started singing before I could talk and dancing before I could walk." Her parents picked up on the cues. They started her at Pat Peare's School of Dance in Eagan, Minnesota, when she was in kindergarten and enrolled her in voice lessons when she was 8. By the time she was in sixth grade, she was doing dance competitions in tap, jazz, and lyrical. At 12, she was working professionally at the renowned Minneapolis Children's Theater.

Crumm, meanwhile, was growing up in Arizona with greasepaint in his veins. His father, Gary, founded a community theater, the Ahwatukee Foothills Theater, and his mother, Rachel, and his older sister, Janelle, were frequent performers. Max, who was dubbed "Slacker Danny" on TV because of his laidback demeanor, went along to the theater with the rest of the family, first just to watch, then to perform. "I get all my comedy from my dad and my singing and dancing from my mona," he says. "I was born into it." He took some tap lessons as a child, but for the most part, he learned to dance informally. "On Saturdays we would clean the whole house with music on," he recalls, with his mother teaching dance steps along the way. He made his stage debut in Anything Goes, "as a little dancing sailor."

Whatever chemistry Osnes and Crumm bring to their roles in Grease will be genuine. They met early on, when both were auditioning for You're the One That I Want in Los Angeles. No TV screenwriter would dare put this in a script, but there were eight people between them in the callback pool, and all were eliminated. "So we were sitting next to each other by the third day," says Osnes. When they began chatting, exchanging the mandatory hometowns, it turned out that his roommate was from her area and that they were pals.

In addition to knowing the roommate, Osnes and Crumm also knew Grease, inside out. She was playing Sandy at the Chanhassen Dinner Theater (which bills itself as the world's largest) outside Minneapolis. He had already moved to L.A., but he'd performed in the show at the Valley Youth Theater near Phoenix.

Grease itself can only be called a phenomenon, and it was a phenomenon right from the beginning, in Chicago in 1971. It's hard to remember today that back then, Broadway musicals did not come from Chicago--or anywhere else, for that matter. I recall being both mystified and very skeptical when I heard about it--some spoofy show mocking the '50s that had become a bit of a craze in Chicago and was coming to try its luck in New York, at the down town theater just vacated by Oh! Calcutta! (also a phenomenon, but that's another story).

Well, what did I know? Jim Jacobs, who joined producer David Ian and director Kathleen Marshall to judge You're the One That I Want, and Warren Casey, who died of AIDS complications in 1988, had written a sharply observed but gentle-hearted parody of the music and mores they--and I, and several million other baby-boomers--had grown up with. The jokes began with the poodle skirts, and continued with the pastiche score and the cool-cat moves choreographed by Patricia Birch.

Grease was huge, moving to Broadway, earning seven Tony nominations--including one for Birch--and setting records as it ran for eight years. The 1978 movie dispelled the original's satiric bite, but made the show a cultural touchstone. And if there ever was any chance that it would eventually disappear, that's been effectively eliminated by the television series. It was not particularly successful as a TV show but was incredibly effective as a marketing tool for the revival, which begins performances this month.

For Osnes and Crumm, both 21, it is, as advertised, the chance of a lifetime, and they are savoring it. With their store of experience, they were confident they could carry a Broadway show. They'd already been through the wringer, they said, with the pressure-filled weeks of You're the One That I Want, and they had survived. And, having gotten to know Marshall, they were looking forward to working with her on the real thing.

Having had years of dance class, Osnes was hoping that Marshall would up the ante on the choreography for Broadway: "During the live TV show, we had to simplify it, because there was so little time and not everyone was a dancer." But Crumm wasn't worried, convinced that even without much formal training, he could pull off whatever dance moves Marshall threw at him: "I've got good rhythm and good motor skills. I'm not a weak dancer. I'm just not trained." He did have a request, though. "Don't get mad at me if I don't point my toe."

Sylviane Gold has written on theater for Newsday and The New York Times.