Joan Rivers claims that Kristen Stewart is suing her over an extract that she wrote in her book, Diary of a Mad Diva, which implies that the Twilight actress owes her career to "being able to juggle a director's balls".
Her comments allude to the Stewart's 2012 "momentary indiscretion" with director Rupert Sanders, who she worked with on Snow White and the Huntsman.
Sanders was then married to model Liberty Ross, with whom he has two children. They are now divorced.
"Many stars only do one thing well," wrote Rivers.
"Of course, the best one-trick-pony is Kristen Stewart, who got a whole career by being able to juggle a director's balls."
The comedian, who is known for her sharp tongue and often controversial comedic views, says that Stewart has since filed legal action.
"I am now being sued by Kristen Stewart," Rivers told a TMZ cameraman.
"She obviously didn't read our disclaimer, which says it's a comedy book. I can't wait to get her into court because I'm gonna get a puppet and I want her to show me on the puppet where she thinks I claim she touched her director. I am looking forward to it."
Rivers remains unconcerned about the prospect of a lawsuit.
"Her lawyer contacted my lawyer, which shows the sense of humour she has," said the 81-year-old.
"My answer to her was, 'Be glad you're not a Kardashian because they're mentioned a lot more in the book.' I'm a comedian. I've been doing it for 50 years. If people don't get it, then don't come and see me. It's okay. Don't read the book. If you're gonna take it seriously, you're a fool."
Other high-profile names to find themselves on the receiving end of Rivers in her latest book include Pharrell "and his stupid hat", Bethenny Frankel and Paris Hilton.
"It's all over the news that Angelina Jolie had a double mastectomy to prevent getting cancer," wrote Rivers.
"I think Paris Hilton should step up to the plate and try to prevent STDs. It would be so easy for her. All she would have to do is have her knees fused together."