Joan Rivers had some harsh words for Gwyneth Paltrow on Watch What Happens Live Credit: Charles Sykes/Bravo/NBCU Photo Bank; Pascal Le Segretain/Getty Images

Your move, Gwyneth. Joan Rivers threw down the gauntlet during her Watch What Happens Live appearance on Wednesday, April 17, when a viewer asked which stars had given the comedian a hard time about her Fashion Police jokes.

"The worst criticism was, ugh, Gwyneth Paltrow," the red carpet veteran answered without pause. "She came and yelled at us, but she stood up. She can't sit down 'cause she's got a stick up her rear end."

Host Andy Cohen laughed, but Rivers, 80, wasn't done. "The world's most beautiful woman voted by Helen Keller and Stevie Wonder," she scoffed of the Oscar-winning actress and recently separated Goop founder, 41. "Not my favorite."

The feeling is mutual. Paltrow took a public dig at Rivers back in 2013, when she was asked about her beauty routine during an interview with Harper's Bazaar.

"I've probably tried everything," she told the magazine. "I would be scared to go under the knife, but you know, talk to me when I'm 50. I'll try anything. Except I won't do Botox again, because I looked crazy. I looked like Joan Rivers!"