Did you know that Scarlett Johansson is a singer? Or that Entourage-actor Adrian Grenier is a drummer in the band The Honey Brothers? Well now you know! Some of our favorite actors/actresses are just a little more hipper than their colleagues. We just love a man in a band and we are so jealous of those women that can both act and sing! Here are our favorite rock star celebs! Which one is your favorite?