"Real Housewives of New Jersey" villain Danielle Staub was up to her cougar ways last week at the launch party for Mademan.com in New York City. And this time, she was ready to sink her claws into a well-known former "American Idol" contestant, FOX411 has learned.

Constantine Maroulis, 33, who is starring on Broadway's rock-and-roll hit parade "Rock of Ages," is still best known for his sixth-place finish on Season 4 of "Idol." (If you've forgotten, he did that little "call me" thing with his pinky and thumb when it was voting time - charming.) Maroulis, who was nominated for a Tony for his role in "Rock of Ages," was at the Mademen.com event, during which Staub was surprised with red velvet cupcakes to celebrate her 47th birthday, which, in turn, she only wanted to share with the faux rocker.

"She was flirting with him hardcore, which wasnt a total surprise, since he is her type - young, handsome and the creative type," an eyewitness tells FOX411. "The birthday girl was at the top of her game feeding him cupcakes and being cute with the icing."

So was Maroulis reciprocating?

"Constantine has a girlfriend and really wasnt having it," says the snitch.

Rock on, Constantine.