DEBBIE REYNOLDS & EMMA WATSON: 23
By 1955, Reynolds had tap danced alongside Gene Kelly in Singin' in the Rain and been named America's sweetheart, courtesy of her girl-next-door good looks – or make that woman next door; those curled bangs certainly add a few years! Watson, meanwhile, hardly looks a day out of Hogwarts, despite graduating to edgier roles. "The allure of being sexy never really held any excitement for me. I've never been in a terrible rush to be seen as a woman," The Bling Ring star told W magazine.