Mary-Kate and Ashley Olsen Open Up on Their Style and Design Process

One can always rely on Mary-Kate and Ashley Olsen for a few things — to look incredibly chic on the red carpet, to produce the best fashion-forward minimalist designs for their brands and always be the most tight-lipped style icons on the scene. They’re notorious for leading super-private lives, which makes InStyle‘s candid interview with the designers in its September issue all the more exciting. To celebrate their new Elizabeth and James store in L.A., they spill on their style icons, vintage obsession and what’s next for their careers. (Will they ever jump ship to design for another fashion house?)

One reason the sisters’ style has become legendary is their dedication to vintage pieces. “There’s something nice about knowing you are the only person in the world who has it,” explains Mary-Kate. “It’s sort of like buying art. For everything that we call modern today, think about pieces made in the ’20s and how modern they looked then and now.”

Ashley has similar feelings about what constitutes great fashion. “Quality and scarcity,” she says. “You look at these pieces and you have an emotional reaction, not just because they are pretty objects, but because they look and feel different from what is possible to do currently.”

Slightly harder to define than what makes fabulous fashion? How they feel about each other. Mary-Kate calls Ashley “loving and consistent,” while Ashley returns the compliment with “You are the most grounded, brutally honest and compassionate person … and my best friend.”

It’s that closeness that allows them to have joint and total control over their brands Elizabeth and James and The Row. “It’s important to control the image of your brand, something we have known since we were very young,” Mary-Kate says of the decision to produce their ready-to-wear collection themselves instead of using an outside licensee. “It’s a lot more work but we’re up for it.”

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And the duo is really involved in every step of the process of getting a garment produced, from the materials used to calculating shipping details. “Design has become really mathematical in a way, and for us, there’s a freedom that comes from knowing exactly where we want to go from the start.”

As for their personal fashion influences, Ashley notes Coco Chanel or Mariano Fortuny as designers she’d love to meet, while Mary-Kate would rather admire their work from afar.

“Sometimes you don’t want to meet them,” says Mary-Kate. “For me, it’s interesting to see how different designers have affected other houses throughout the years. When you look at the work of John Galliano or Karl Lagerfeld, it changes your perspective of a house.”

So, will we see them take the reins at a couturier in the future? Odds are slim.

“We are so fortunate to have each other. We hired every person on our team. We have full control, and we’re lucky to be under one roof. That you cannot take for granted,” says Mary-Kate.

Are you fans of Elizabeth and James?