Stewart has called Ultimo's boss Michelle Mone "a manipulative cow," Britain's Sun reported Monday, following Mone's March 22 comments Stewart's girlfriend, Penny Lancaster, had only been hired by the company because she was cheap.
Mone's slurs about Lancaster came at Ultimo's spring launch when the company announced Lancaster had been replaced by supermodel Rachel Hunter, 35, Stewart's estranged wife.
"Penny worked her bloody (expletive) off for Michelle. Michelle's treated her horribly; she is a nasty piece of work," Stewart, 59, said. "If this drums up more publicity for her bra company I hope Michelle chokes on the profits."
Stewart said the insults left Lancaster, 33, in tears.
"It's disgusting to call my girlfriend cheap," he said. "Penny hasn't a bad bone in her body, but Michelle's entire skeleton reeks of self-interest."