Washington, June 23 : Kristen Stewart had threatened to sue Joan Rivers for writing in her book ' Diary of a Mad Diva' that she bought her way to stardom through casting couch.

According to TMZ. com, the 81-year-old star called the 'Twilight' actress "one-trick-pony" in her book, saying that the 24-year-old beauty made her career by sleeping with a director, referring to her affair with the married director, Rupert Sanders.

It is believed that Stewart's lawyer had contacted River's associates and asked to remove the comments, failing which Rivers would be sue d for defamation, but as per Joan's people, the prologue of the book clarifies that the remarks are intended only for laughs. (ANI)