updated 07/07/2011 AT 11:05 AM ET
•originally published 07/07/2011 AT 11:45 AM ET
What could get Justin Timberlake a little out of synch?
How about having his mother walk in on him while he was having sex.
“I was caught one time,” the Friends with Benefits star, 30, tells Elle’s August issue. “My mom wasn’t cool about it. I was too young to be in bed with a girl, so she was upset.”
Fast-forward all these years later, Timberlake is still nervous about what mom thinks.
“I’m still trying to get into the editing room and cut down on my ass time,” he says of the frequent scenes in which he bares his bottom in his latest film. “I m like, ‘Oh my God, my mom’s gonna see that!’ ”
Not concerned with Timberlake’s mother’s reaction to the nudity-laced flick, the actor’s costar Mila Kunis, 27, believes the more booty shots, the better.
“You’ve got a fine ass,” the actress tels Timberlake during the interview.