Mary-Kate Olsen insists her fashion line with sister Ashley isn’t “fast fashion”.

The American twins have three successful fashion labels, The Row, Elizabeth and James and Olsenboye, which all appeal to different markets. The Row is a luxury high-end brand and boasts a host of celebrity fans, with Heidi Klum recently spotted in a dress from the range.

Mary-Kate, 25, says a lot of workmanship goes into the line.

“It’s not fast fashion,” she told British newspaper The Telegraph. “We pay so much attention to the fit and the quality and the details.

“It takes a lot of discipline. But we’ve always been very driven, and we enjoy what we do. It’s what we know.”

Mary-Kate and Ashley are famed for their petite frames. The fashionistas were child stars -and with a lack of labels producing childrenswear, they often had adult clothes from labels such as Chanel cut down to fit.

“We loved it!”Ashley exclaimed. “We’d go through racks and racks of clothes, and hours of fittings. When you cut something down that small, it has to be precise. So we’ve always been really interested in fit.

“And over the years we’ve become more educated in fabrics and make, and appreciating those small details. That’s where we start from now, always – what feels right.”

Their attention to detail is apparent with their designs. Ashley says a lot of thought is put into the way the pieces fall on a woman’s body.

“It’s about the drape and the fabric. And finding the balance between the two,” she said. © Cover Media