A new book claims that actor Marlon Brando and former U.S. first lady Jacqueline Kennedy Onassis shared a passionate affair in 1964, something Brando had wanted to include in his 1994 memoir.

But an editor at Random House who was friends with the former first lady encouraged him to leave the details out, according to Page Six.

“I’m not sure she knew what she was doing sexually, but she did it well,” Brando wrote, according to an excerpt from the new book.