Mila Kunis Talks About Casting Her Butt Double

Auditioning is tough, even for body doubles, as Mila Kunis revealed on Ryan Seacrest's radio show Thursday morning. 

The star of the raunchy RomCom Friends With Benefits, which opens Friday, explained how her butt double for some of the film's nude scenes was chosen. 

“These young ladies came in,” she explained. "They were in a casting room and I was there, the director and the casting director and my makeup artist were there. And these lovely women had to show us their derrieres and we chose the one that resembled my body the most without looking like it’s fake."

But, Kunis didn't require body doubles for all of the revealing scenes. So, what caused the posterior shyness? 

"I showed side-boob, and I figured I can’t just give away everything all at once," she joked. "I gotta let it all out in little pieces here and there."

Her co-star wasn't as demure. Justin Timberlake's rear end is prominently featured in the film.

"I only did it because I’m young now, and everything’s where it’s supposed to be," singer-turned-actor has said of of the nudity. "I figured this is the time, before gravity gets the best of me."