News Jackie Kennedy's Sister, Lee Radziwill, May Have Had an Affair with John F. Kennedy By Isabel Jones Isabel Jones Instagram Twitter Isabel is an Oregon-born and Brooklyn-based writer and editor with a special interest in pop culture. InStyle's editorial guidelines Updated on September 25, 2018 @ 09:15AM Pin Share Tweet Email Though tales of the glamorous Jackie O. as well as the tragic Kennedy curse stole the cultural spotlight long ago, the true ingenue of the multi-generational diaspora may not be a Kennedy at all. Jackie’s little sister, Lee Radziwill, sought the spotlight from a young age. And though she did receive her share of fame, to this day she’s incensed by her lifelong qualification as Jackie Kennedy’s sister. Bettmann/Getty Images A new biography from Nancy Schoenberger and Vanity Fair’s Sam Kashner, The Fabulous Bouvier Sisters: The Tragic and Glamorous Lives of Jack and Lee, focuses on the complex relationship between the late Jackie, who succumbed to non-Hodgkin's lymphoma in 1994, and Lee, 85. With every revelation in this taut and fascinating work, Jackie’s final will looms in one’s mind — her pointed exclusion of Radziwill from the 38-page document remains somewhat mysterious nearly a quarter of a century later, though The Fabulous Bouvier Sisters supplies a convincing argument as to why Radziwill may have been cut. In the final pages of the book, what is perhaps the most shocking claim is laid bare: Lee may have had an affair with John F. Kennedy. Bettmann/Getty Images Writer Gore Vidal, who shared a stepfather with Lee and Jackie, once wrote that Lee’s first husband, Michael Canfield, confided in him that his then-wife had slept with her brother-in-law. “There were times when … I think [Lee] went perhaps too far, you know?" Canfield allegedly told Vidal. "Like going to bed with Jack in the room next to mine in the south of France and then … boasting about it.” Why Jackie Kennedy Allegedly Disapproved of JFK Jr.'s Relationship with Madonna As the biography notes, it’s unclear whether Vidal is telling the truth. He bore a complex relationship with both sisters through the years and was known for a proclivity to gossip. However, this would make any resentment Jackie would harbor toward Lee — even in her dying days — logical.