Roberto Cavalli has accused Michael Kors of "copying everything".
The Italian designer is known for speaking his mind and has taken pot shots at Giorgio Armani and Dolce & Gabbana in the past.
Kors is the latest designer to be in the firing line, with Cavalli scathing in his critique of the American star's talent.
"Mr Michael Kors, he copies everything!" he told Haute Living Miami magazine, according to The Hollywood Reporter.
"It's really a scandal and nobody has the courage to say anything. It's really not fair."