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."