Mary-Kate and Ashley Olsen's fashion label has been a ''constant learning process'' for the last decade.

The Row creators have admitted that they are still learning about the fashion industry despite nearly a decade at the helm of their own fashion label.

Mary-Kate said: ''We built the brand from the ground up, and it has been a constant learning process over the last 10 years.''

The twins also revealed their style muse is artist and writer Beatrix Ost, who is in her seventies.

Mary-Kate added to ELLE magazine: ''Beatrix is such a fascinating, strong woman, with such effortless style. She embodies the spirit of the brand.''

It has been a mixed year professionally for the sisters, after they were named Womenswear Designers of the Year at the 2015 CFDA Fashion Awards.

However, their success has been tainted by a lawsuit brought against their company by interns, who claim they weren't paid for their work.

The company Dualstar, though, has deemed the allegations ''groundless''.

In a statement, on behalf of the company, a spokesperson said: ''As an initial matter, Dualstar is an organisation that is committed to treating all individuals fairly and in accordance with all applicable laws. The allegations in the complaint filed against Dualstar are groundless, and Dualstar will vigorously defend itself against plaintiff's claims in court, not before the media.''