LOL! Watch Simon Cowell & Howie Mandel Get Cheeky on ‘America’s Got Talent’ Red Carpet

America's Got Talent: Jimmie Herrod performs last during first semifinals and becomes frontrunner

Heidi Klum and Sofia Vergara lead the red carpet at America's Got Talent semifinals

Simon Cowell chows down on a burger whilst he takes his son Eric on a playdate in Malibu