Comedian Joan slammed the 23-year-old Hunger Games actress in a Twitter rant on Tuesday night (12 November), describing her as arrogant.
The bad feeling started when Jennifer told an interviewer last week that programmes like Joan's Fashion Police, which also features Kelly Osbourne, encourage people to judge each other based on appearance.
Jennifer said: "[Shows like that] put values in all the things that are wrong and [say] that it's OK to point at people and call them ugly and call them fat and they call it 'fun' and 'welcome to the real world.' And it's like, that shouldn't be the real world.
"That's going to keep being the real world if you keep it that way. It's not until we stop treating each other like that and just stop calling each other fat ... with these unrealistic expectations for women."
Sharp-tongued Joan, however, was quick to fire back via Twitter, claiming that Fashion Police had been nothing but kind to Jennifer during awards season when she was picking up gongs left, right and centre for her role in Silver Linings Playbook, including the 'Best Actress' prize.
Joan wrote: "It's funny how Jennifer Lawrence loved @E_FashionPolice during Awards Season when we were complimenting her every single week… But now that she has a movie to promote, suddenly we're picking on all those poor, helpless actors."
She added: "WAIT! It just dawned on me why Jennifer Lawrence fell on her way up to the stage to get her Oscar. She tripped over her own arrogance."
Jennifer is currently promoting Catching Fire, the second movie in the Hunger Games series, so there will no doubt be a million and one interviews coming up where she has the chance to respond...
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