Did Petra Steal Sean Penn?

Sean Penn's been married to Robin Wright and Madonna, and now he’s set his sights on Petra Nemcova.

When the actor showed up at the Elton John AIDS Foundation Oscar party Feb. 24 squiring the 28-year-old beauty, tongues began to wag. They were also seen at L.A. club Villa the night before.

In December, Sean, 47, announced his split from Robin, 41, his wife of 11 years and the mother of his two children, Dylan, 16, and Hopper, 14.

But the supermodel best known for surviving the Asian tsunami has been dropping hints about the object of her affection since September. (She says he’s on the advisory board of her charity, the Happy Hearts Fund, which helps kids suffering through tragedy.)

During a benefit for Elton's AIDS Foundation that month, she replied, “my new boy!” when asked “sexiest man alive?” before adding, “I can’t say. He’s international.”

During a fundraising gala for her Happy Hearts Fund held in NYC in October, Petra tells me she brought her sister in lieu of a date.

“My date is not right here right now,” she says. “He’s in Europe.”

Anyone we would know?

“I don’t know who you know,” she giggles.

She makes a shy face and zips her lip when asked if he’s an actor.

Again, who is the sexiest man in Hollywood?

“I would say my man, but in Hollywood… there are many,” she says. “I don’t look at men! That’s the biggest lie I’ve ever told, but whatever.”

Finally, how does she keep her fab figure?

“Stress,” she tells me. “It’s the best way to lose weight.”

Petra was last linked to James Blunt, whom she dated for two years until spring 2007.

Otherwise, I do think Petra’s a nice person. She’s very bubbly and always ready with a fun anecdote.

Like this: “I don’t eat junk food, but I love dried fruits. No cookies, no candy, not for now. On Saturday, I went into the fridge and there was an avocado-salsa thing, and I ate the whole jar. It was a big jar. In the morning, I was like, ‘How come I’m full?’ I went swimming the next day.”

She also tells me she’s obsessed with “life” and her best beauty secret is happiness.

“Be happy and be passionate about what you do, and it radiates through,” Petra says.

Hopefully she wasn’t being passionate about someone else’s husband.