Why Is Justin Bieber Hanging Out With Mick Jagger And Lenny Kravitz?

Justin Bieber just posted a picture with two musical legends—how did these three get connected?

'Harry Potter' Casting Call: We Want Mick Jagger, Peter O'Toole In 'Deathly Hallows'

Rolling Stones frontman as Mundungus Fletcher? Or maybe funnyman Ricky Gervais? Check out our dream picks for final flick.