Flashback: It Girls Then & Wow!

Time seems to have stood still for Bo Derek, Ashley Judd and Keri Russell and more age-defying faces of the '80s and '90s

GABRIELLE UNION, 40

Getting older? Bring it on – especially when you look as fresh-faced as Union, who hasn't lost a bit of her youthful glow since 1998. The actress, named one of PEOPLE's 2013 World's Most Beautiful, credits her age-resistant appearance to drinking a gallon of water a day and going without makeup. Her other secret? "I stay young by dating younger!"