Will Smith leaves "The Late Show with David Letterman" at Ed Sullivan Theater on May 22, 2012 in New York City. Credit: Donna Ward/Getty Images

Why so slap-happy, Will?

Will Smith wasn't exactly Mr. Nice Guy at last Friday's Men in Black 3 premiere in Moscow. When a male Ukrainian journalist attempted to kiss the actor, 43, on the lips during a friendly exchange, Smith lashed out -- shoving the man and then slapping him in the face.

Smith finally explained what happened on Late Night With David Lettman. "It was just awkward, Dave," Smith said. "They were like, 'Oh, no, we’re sorry, you know. It’s just his 'schtick,' you know. And I said, 'well, that's why his a** got schtuck.'"

Indeed, the reporter is known in Europe for his silly PDA with celebs.

Sniped Smith at Friday's premiere: "He's lucky I didn't sucker-punch him...Oh, sorry, I said that on camera."

Tell Us: Did Smith overreact?