Mary-Kate and Ashley Olsen turn 25 today. The sisters -- who are fraternal, not identical twins -- have spent their entire lives in the public eye, playing toddler Michelle Tanner on "Full House" and later becoming media moguls and fashionistas.
Think you can tell them apart? Click through our gallery and guess which twin is Mary-Kate. The next photo will reveal which one is her.
Want to check out more famous families? Take out our Stylish Sisters poll here!