Ashley Olsen and Mary-Kate Olsen had their fashion revelation in their teens.

The two actresses were on a press tour of Canada, and at one event, they noticed a strange phenomenon. Hundreds of girls in their audience sported oversize sweaters, big sunglasses and Balenciaga handbags. They were, in short, replicas of the twin sisters, who have been in the entertainment spotlight since they were nine months old but, as teens, had developed their own distinct fashion style.

This story first appeared in the November 3, 2010 issue of WWD. Subscribe Today.

The moment triggered the idea for The Row, which they launched in 2007 with the idea of creating a perfect T-shirt. Since then, the line has evolved into eveningwear, outerwear, knits, men’s wear and sunglasses, and they have since also launched the contemporary Elizabeth and James line and the junior and tween Olsenboye line at J.C. Penney.

In the process, the duo have become role models for celebrities looking to start their own fashion lines. With the exception of Victoria Beckham, few celebrities have garnered the kind of respect from the fashion industry the Olsens have, and the 24-year-olds seem to be living and breathing fashion these days.

And unlike other celebrity designers, they have so far shied away from massive runway productions and runway bows that would be splattered across tabloids a few days later. “We did it because we didn’t want people to buy the clothes because it’s us,” Ashley Olsen said. “We wanted the product to speak for itself.

“We are in such a unique situation,” she added. “People have been watching us since we were nine months old.”

“We were born into it,” Mary-Kate Olsen said. “It was never a choice or an option. For us, it was work.”

The twins deliberately took a quieter approach. “I felt there was something missing from the marketplace,” Ashley Olsen recalled. “I was a shopper. I felt that basic luxury was missing. We started it very small, selling only to one store at a time, starting with Barneys New York. It was completely separate from Dualstar.”

Dualstar is the company the Olsens formed in 1993, when they were six years old and stars of the hit sitcom “Full House.” It manages the sale of special videos and DVDs as well as an apparel collection for Wal-Mart. By the time they turned 18, though, they were ready to move their business, and their image, in a new direction.

“We learned so much,” Ashley Olsen said. “The more control that we could have over the product, the more we wanted to support the product and the happier we’d be.”

The Olsens took an unusual route. Unlike others who start at the designer tier and eventually dilute their brands to the mass level, they went in the reverse direction, making their names at Wal-Mart before building a designer brand at the Barneys tier. The sisters credit the journey with their own coming of age. In fact, The Row’s customer is now aged between 35 and 65, with 45 being the average.

“When we were younger, we had more of a mass audience,” Mary-Kate Olsen said. “As we got older, we worked with things we wanted.”

With The Row, they went after a minimal feel based on fabric and fit.

“We manufacture everything in the U.S. and just started to work with Italy for knits,” Ashley Olsen said, adding there are a variety of reasons for this approach. “We want to save the Garment Center and keep people employed here. With a small brand like this, it also allows us more control.”

“We can nurture the product more,” Mary-Kate Olsen added.

Asked for their day-to-day routine, the Olsens rattled off a schedule that would make any major designer proud. “We are in the office by 9 a.m., depending on where we are in the season,” Ashley Olsen said. “Then we may have a financial call followed by a design meeting.”

“And then an Elizabeth and James meeting,” Mary-Kate Olsen chimed in.

“We meet with licensing partners, and right before the show, it’s not unusual for us to be in the office until 4 a.m.,” Ashley Olsen said.

While Ashley Olsen is clearly more the fashionista of the two, Mary-Kate Olsen had her own design agenda. “I wasn’t as big a shopper,” she admitted. “But I was horseback riding since I was six years old, so it was all about fit for me.”

From Dolce & Gabbana to Proenza Schouler, fashion has its share of design duos, and even if the Olsens take a different approach — at times they disagree on colors, Mary-Kate Olsen said — they still share a common goal. Both see their three lines expanding into full lifestyle brands, and, for The Row, they are planning to add handbags next fall, followed by shoes. “It would be a proper American luxury brand, made in America, with retail businesses and maybe collaborations with other brands,” Ashley Olsen said.