Marc Malkin

Mario Lopez has nothing to be ashamed about when it comes to his body.

But even he has his limits.

The former Dancing With the Stars contestant told me Playgirl has come calling. “I politely declined,” he said with a laugh. “It’s not something for me at the moment. But it’s ironic, because I’m, like, ‘nature boy.’ I’m always running around the house in underwear or nothing.”

Lopez didn’t invite me to hang at his place, but no matter. Just check out his new book, Mario Lopez’s Knockout Fitness.

You’ll see why the New York Post’s Page Six has dubbed the one-time Saved by the Bell teen heartthrob “Flex.”

And while Lopez, currently starring on Broadway as Zach in A Chorus Line but in L.A. tomorrow for a booksigning at the Grove mall, has never divulged too much about his relationship with his DWTS partner girlfriend, Karina Smirnoff, the book shows them in action.

No, not that kind of action!

There’s a chapter dedicated to a dance workout featuring step-by-step photos of the happy couple.

So what about the never-ending breakup rumors? “Is there another one?” Lopez said, laughing again. “I get a kick out of them. I think they’re funny. I think it just kind of comes with the territory. I don’t really put too much thought into it.”