Mary-Kate and Ashley Olsen respond to intern lawsuit

The Olsen twins have hit back at a class-action lawsuit that alleges they illegally used unpaid interns.

Forty current and previous interns sued Mary-Kate and Ashley Olsen's company, Dualstar Entertainment Group, claiming that they should have been paid minimum wage for doing similar work to that of their colleagues' and also not receiving school credit.

Dualstar, which owns fashion labels The Row and Elizabeth and James, responded in a statement to USA Today.

"As an initial matter, Dualstar is an organization that is committed to treating all individuals fairly and in accordance with all applicable laws," wrote Dualstar representative Annett Wolf. "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. Dualstar is confident that once the true facts of this case are revealed, the lawsuit will be dismissed in its entirety."

The federal Fair Labor Standards Act mandates that unpaid internships at for-profit companies must be "for the benefit of the intern" and "similar to training which would be given in an educational environment."

Moreover, the intern is there not to "displace regular employees, but [work] under close supervision of existing staff."

Lead plaintiff Shahista Lalani claimed she worked 50 hours a week creating spreadsheets, running errands for paid employees, cutting patterns, photocopying and sewing, but wasn't paid, according to the AP.

Some companies, such as Conde Nast, have discontinued unpaid internship programs.