Thanks to his movie Friends with Benefits (co-starring Mila Kunis), Justin Timberlake is opening up about his sex life.  He says that he was even caught by his mom once, and she wasn't happy!  Timberlake said, "My mom wasn’t cool about it. I was too young to be in bed with a girl, so she was upset."  Yikes.  Still, it's good to know that celebrities really are just like the rest of us!