Mary-Kate Olsen was working in show business when she was just a tiny tot. Now the megamogul and one-half of the Olsen twins has staked her claim in TV, film, video, fashion and even home decor! Mary-Kate is on the cover of Elle magazine this month, where she talks about everything from her sister to her celebrity status.

"It's weird to be called a celebrity," she says. "I mean, if I see a paparazzi shot of me walking that's in a magazine or something at some event, it's as if I see it from an outsider's point of view. There's like a character, almost, and then there's me. I think it's kind of entertaining."

As for her differences with her sister Ashley, Mary-Kate admits they don't always see eye-to-eye, but their bond is deep. "Unless you're a twin, you honestly can't know how close twins can be," she explains. "When there's that much love there's ... well, there's the opposite of everything, but it stems from love, and it stems from passion. We're driven people."

Hey, bad hair days can happen to anyone -- even celebrities. Sure, they've got the big guns styling them for the cameras, but bad decisions have been known to be made.

Stars like Christina Aguilera, Alicia Keys and the ever-experimental Olsen twins have gone down the red carpet with super questionable hairdos that make us cringe, but by the same token, they've also shined with the most glamorous tresses. Check out the good, the bad and the just plain ugly in this Stylelist gallery.