The former rom-com queen's acting career has taken a back seat to motherhood (she adopted daughter Daisy in 2006) but her wide smile and tousled locks will always be welcome on the big screen.
She's not the only Hollywood star who turns the big 5-0 this year.
Heather Locklear, George Clooney and Dylan McDermott (who's never looked better) all celebrated the milestone birthday in 2011. Others include several 80s stars, a "Beverly Hills 90210" alum, a "Real Housewife" and more!
Click on the "Launch Gallery" button below to see who is 50 and fabulous!
And here's the kicker -- all of the photos in the gallery were taken this year!