We're wishing Drew Barrymore a big happy birthday today! The actress, producer, beauty-line founder, and mom to little Olive has always been a fan of makeup and beauty, and so for her 38th, we're looking back at some of her most memorable looks ever (just last year, she changed her hair three times!). "I’ve been sitting in the makeup chair since I was a kid. It’s something I know and love," Barrymore told InStyle. "I just think happiness is what makes you pretty. Period. Happy people are beautiful." Click through the gallery to see the birthday girl's beauty evolution!