Ever imagined what Perez Hilton was up to before his rise to internet fame? What about ladies' man and Grammy-nominated singer Trey Songz? Would you believe us if we told you he was a barber in training? Well, you don't have to take our (blog) word for it. MTV's new weekly show, "When I Was 17," will explore the pasts of three different celebrities each episode, kicking off with Perez, Trey and Khloe Kardashian this Saturday at 11/10c. Tune in to find out how these stars behaved at 17, but first, check out this sneak peek of the premiere: