Justin Timberlake is starring in a new movie about friends who use each other for sexual benefits but there is one awkward sexual moment the star would like to forget. Timberlake revealed how one time his mother caught him having sex with a girl and she was very upset about it because the singer was too young at the time to be in bed with a girl. Timberlake recalled the humiliating encounter in an interview with Elle magazine while promoting his new film Friends with Benefits where his character and Mila Kunis’s character make a pact to forge a strictly physical relationship with no emotions and just sex.