Unlike some celebrity clothing designers, Mary-Kate and Ashley Olsen are involved with each aspect of the apparel-making process.

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As the head designers of three separate clothing lines -- The Row, Elizabeth & James and Olsenboye -- the 24-year-old sisters have brought in $1 billion in retail sales through their company, Dualstar. Still, Mary-Kate and Ashley tell Vogue's April issue that buyers weren't always so supportive of their fashion venture.

"We hired a showroom and talked buyers through," Ashley recalls. "People would drill us about fabric, where we'd make it," Mary-Kate adds. "The first season, customers bought it, so the stores came back. And drilled us again."

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Still, the twins realized that with no formal design training under their belts, they were in for a tough sell.

"It's a fair question," Ashley notes, "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," Mary-Kate points out. "It would be jeans, a bit bohemian, or with a little blazer. It was really fashion-forward."

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These days, the well-established sisters are finally being recognized for their achievements: they received their first ever CDFA nomination this year. (The twins will face off against Joseph Altuzarra and Prabal Gurung in the Swarovski Award for Womenswear category).

"It's classicist, no-bother stuff. I live in it," raves celebrity fan Lauren Hutton, who once modeled for the The Row's look book. "It's beautifully tailored in a modern way. It just fits, chicly. You know, I look up to them."

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With rave reviews and celebrity fans like Carey Mulligan, the former child stars show no signs of slowing down in the near future.

"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."

"The thing about us," Mary-Kate interjects," is we think big. Huge."

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