The handsome actor revealed a particularly embarrassing occasion that still makes him cringe.
"I was filming this movie called The Lucky One and I stayed in this pretty cool apartment," Efron, 26, recounted to Fallon. "One day I was laying on the couch in my underwear and the door opened and someone walked in. I heard the 'click clack' of high heels so I knew it was a chick!"
"I jump up and it's [New Orleans Saints] Coach [Sean] Payton and a girl he was with. They just let themselves in because somebody told them they could view it because they were planning on renting the apartment," the hunk continued. "So there I was, facing Coach Payton, someone I really admire, in my boxers going, 'Very nice to meet you, huge fan. Can I put pants on?'"
But funnyman Rogen used his influence to prank Efron into showing more skin than was strictly necessary.
"I idolize Seth, he's my hero," explained Efron. "I would literally do anything he asked. He would say, 'Zac, shirt off' and I'd be like, 'Yes sir!' Eventually I realized the cameras weren't even pointing in my direction. He was just f--king with me."