04/27/2011 11:43 am ET Updated Jun 27, 2011

Justin Timberlake, Mila Kunis Talk Friends With Benefits

Justin Timberlake plays a guy in a casual relationship with his friend in the new movie Friends with Benefits -- but the singer-actor isn't such a fan of casual hookups in real life.

"It's a really good idea until it becomes a bad idea," Timberlake tells Ellen DeGeneres in an interview with his costar Mila Kunis scheduled to air Thursday. "It probably becomes a bad idea really fast."

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