We Think Big, Huge.

Mary-Kate and Ashley Olsen have been celebrities since before they can remember, and unlike some former child stars, the twins, now 24, have come through the fame gauntlet (relatively) unscarred. Though there have been a few bumps in the road, the two are now respected fashion designers -- and the best bit is, they actually design the clothes themselves. In a revealing interview with Vogue, the two open up about their style, their business empire, and each other.

With a shared height of 5'1", the Olsen twins are diminutive, to say the least, but don't let their size fool you. At 18, these two tiny young women bought out the former owners and took control of their company Dualstar, which has seen retail sales of over $1 billion since it was formed when the twins were six. What qualified them to take over a corporation on the day they were legally able to vote? "Well, at that point we had been working eighteen years," demurs Mary-Kate.

The twins are now the head designers of three successful, separate clothing lines aimed at all levels of the market. The Row is aimed at the luxury end, Elizabeth & James at the contemporary market, and the affordably priced Olsenboye at the teen mass market.

Like most celebrity designers, there was doubt that the girls actually designed the duds by themselves. "It's a fair question," Ashley admits, "but Dualstar started when we were six. And we had a collection with Walmart at 12, which was the upper tier of the tween market. It was before celebrity designers."

"And we were really designing it," adds Mary-Kate. "It would be jeans, a bit bohemian, or with a little blazer. It was really fashion-forward." Of the two, Mary-Kate is considered to be the creative one, while Ashley is the business mind, but in truth the two share a very symbiotic relationship. "Some of our memories are shared," reveals Mary-Kate, adding, "We don't know what actually happened to whom. One of us was stung by a bee, but we can't remember who, because we both felt it."

 Also shared? The twins' enormous wardrobe. When asked if there is a demarcation line between their closets, Ashley replies, "Hmm. There's hers, there's mine. And a huge 'maybe' pile."

With rave reviews from fashion buyers for their new The Row collection, and celebrity fans including Lauren Hutton -- "It's classicist, no-bother stuff. I live in it," -- and Carey Mulligan, the former child stars are designers on the rise, and they show no signs of stopping any time soon.

"I want to run a studio," Ashley announces. "I'd probably like to manage other people on their brands. It could be an artist. A young designer. It could be an existing brand." Adds her twin in all seriousness, "The thing about us is,