Author Missy Chase Lapine has filed a lawsuit against husband and wife Jerry and Jessica Seinfeld over defamation and copyright and trademark infringement.
Ms Lapine claims that, after her publishers raised the issue of potential copyright infringement over a cookery book that the Seinfelds had released, Mr Seinfeld went on to launch a malicious campaign against her, publically calling her a "nut job" and "hysterical".
Her lawsuit also cites an appearance by Mr Seinfeld on the Late Show With David Letterman in which he reportedly described Ms Lapine as a "wacko" who had been "waiting in the woodwork" for an opportunity to attack the Seinfelds.
It is also alleged that he incorrectly asserted that Ms Lapine's and Ms Seinfeld's books came out at the same time, when in fact Ms Lapine's publication was released six months earlier.
Jerry and Jessica Seinfeld married in December 1999 and have three children together.