Holla! Party girl Mischa Barton has an actual reason to party it up today: It’s her 25th birthday! Believe it or not, when the actress hasn’t been going on beer runs, chucking litter from cabs (allegedly) and cruising around the world getting high, she’s actually been hard at work: making movies, taping TV appearances and developing a fashion line — even reportedly campaigning to cha-cha on “Dancing With the Stars.”

To celebrate, we’ve assembled a retrosextive of her finest photo shoots — just click the images to for an all-access pass to our sexy Mischa Barton Birthday Party!

Mischa Barton Needs a Kiss
Mischa Barton Lives the High Life
Mischa Barton Rolls Wonky Joints