The 65-year-old Guess co-founder and creative director denies the allegations, but the company’s board of directors has commissioned an investigation by outside lawyers into the claims of improper conduct.
“The board of directors and Mr Marciano have agreed that Mr Marciano will relinquish his day-to-day responsibilities at the company, on an unpaid basis, pending the completion of the investigation,” Guess said in a statement.
Marciano said the company would have his “full cooperation.”
Following the announcement, Guess shares were down 3.8 percent on Wall Street.
Upton, who was once the face of the label, first accused Marciano on Twitter, before detailing her allegations in an interview with Time magazine as the #MeToo campaign against sexual misconduct widens within the fashion industry.
The 25-year-old told Time that after a July 2010 lingerie shoot, Marciano “forcibly grabbed my breasts and started feeling them — playing with them actually.”
After she pushed him away, she said he continued to touch her “in a very dominating and aggressive way” and at one point “forcibly grabbed the back of my head so that I could not move and started kissing my face and my neck.”
A month later on another shoot, she said Marciano repeatedly asked to come up to her hotel room, but that she turned off her phone, locked the door and tried to sleep.
“I was terrified. All I could think was if he was able to get into my room, it would not be good,” she said.
“The next day, I learned that I had been fired from the shoot. Someone had called my agency to say I had gotten fat and would not be needed on set.”
Marciano co-founded Guess in 1981 and has been its executive chairman and chief creative officer since 2015.
Upton is married to star Houston Astros pitcher Justin Verlander, and is known for appearing on the cover of Sports Illustrated swimsuit editions.