The founder of an Italian fashion house beloved by Taylor Swift and Gigi Hadid fired a female employee for being “fat” — while paychecks for women workers are anything but, a new lawsuit claims.

Celeb-chic fashion house Etro has a “dark and malevolent” work environment where head Gimmo Etro discriminates against underlings because of their appearance and age, and women make thousands less than their male counterparts, an ousted HR director is charging.

Kim Weiner says she was canned from Etro’s US division in June after 25 years with the company for standing up to its discriminatory practices.

“Etro’s glamorous public image has long concealed a dark and malevolent secret,” Weiner says in the new Manhattan Supreme Court suit.

She says founder Etro urged Weiner to oust a longtime cashier because she was “old, fat and ugly.” Weiner also claims a male vice president made $200,000 a year while his female counterpart only earned $130,000. A spokeswoman for Etro did not return messages seeking comment.