Natural hair color: Blonde

Why she went red: Judd Apatow told her to do it for Superbad (2007), and people do what Judd Apatow says. It turnedout to be a brilliant move; Emma's fake red hair became her calling card, and this fall, it was reported by InStyle that the most popular hair coloring requested in L.A. salons was that deep Emma Stone-crimson. Of course, by then, Emma had gone blonde to play Gwen Stacy in a couple of The Amazing Spider-Man movies.