"You're joking, right?"

Gregg Gillis hears that a lot, as well he should. Anyone who builds cutting-edge dance music from samples of Styx, Huey Lewis and Kenny Loggins has to be kidding, doesn't he?

The funny thing is that he's dead serious.

"This is not ironic. I'm fascinated by mainstream pop music," he says. "You might think Hall & Oates are slightly nerdy or you might hate Styx, and that's fine with me. But maybe you'll like the way I manipulate them into this project."

The project is Girl Talk, the nom de rock the 26-year-old Pittsburgher uses for his electronic mash-ups. Gillis has become the darling of underground music for his unlikely fusions of Phil Collins and the Wu-Tang Clan, and he's played to rapturous crowds at Lollapalooza, Coachella and Bonnaroo.

It all started in third grade with a cassette tape of Bell Biv DeVoe. Later, he became a fan of Nirvana, which led him to Sonic Youth. And before he knew it, he was creating experimental music on a laptop computer.

"My first band at 15 was complete noise with no melodies, but at the same time, I was still into 'N Sync and the Spice Girls and the art of overproduced pop music," he says.

So he decided to merge the two and smash the boundaries between hip and square.

"I love all sorts of music," he says. DMN

Gillis has released four albums online, including the new Feed the Animals, which he offers on a pay-what-you-want basis at illegalart.net. Built around about 200 unauthorized song samples, the album was recently dubbed "a lawsuit waiting to happen" by The New York Times. But nobody has tried to sue him, at least not yet, he says. "People are getting used to how everyone remixes media," he says. "That's the way the world works right now, and I think major labels realize that."

In concert, Gillis is a madcap performer who bangs his head, drops to his knees and strips down to his skivvies (or sometimes, even less). He's not a DJ, but a rock musician who happens to use a laptop instead of a guitar. "It's based on samples, but I'm jamming and transforming it into something new," he says. "I'm a live performer."

Girl Talk performs tonight at 7:30 at the Palladium Ballroom, 1135 S. Lamar. $15. Ticketmaster.