What exactly did Jackie Kennedy think about JFK鈥檚 long-rumored relationship with Marilyn Monroe? A new biography of the 35th president, JFK: Public, Private, Secret has some surprising answers.
According to author J. Randy Taraborrelli, Jackie once said to her husband of Monroe, 鈥淭his one鈥檚 different Jack. This one worries me.鈥
鈥淭hat鈥檚 from somebody who was right there in the White House who overheard that conversation,鈥 Taraborrelli tells PEOPLE. 鈥淚t was reported to me 25 years ago, when I was writing an earlier book, Jackie, Ethel and Joan.鈥
For more on JFK and Taraborrelli’s new book, pick up the latest issue of PEOPLE, on newsstands Friday, or subscribe here.
According to Taraborrelli, 鈥淪he [Jackie] didn’t know the nature of the relationship but knew him well enough to suspect something was going on. What鈥檚 really important is her use of the language: 鈥楾his one鈥檚 different,鈥 suggesting very strongly she was okay with the other [women] but this one was different.鈥
The conversation took place before JFK鈥檚 birthday party on May 19, 1962 at Madison Square Garden, he says. 鈥淪he didn’t want anything to do with it. She had a barbecue with the Auchinclosses [her mother Janet Auchincloss and stepfather, Hugh Auchincloss] rather than go because she did not want to endorse it.鈥
As for the long-rumored affair between JFK and the star, Taraborrelli says, 鈥淚 don鈥檛 have enough evidence to support it,” especially when it comes to a weekend in early 1962 when it鈥檚 long been claimed the President and the star both stayed at the home of Bing Crosby.
Taraborrelli spoke to Pat Newcomb, now 96, who was Monroe鈥檚 publicist 鈥 and a close friend 鈥 who told him the star was not there that weekend.
鈥淧at said 鈥業鈥檝e been reading about this for 60 years and I can tell you that this did not happen,鈥 鈥 says Taraborrelli of the specific meeting. 鈥淚f that didn鈥檛 happen then, I don鈥檛 know when they were together because then it was a clear shot to Madison Square Garden, where she sang Happy Birthday Mr. President and then she was gone.鈥 Monroe died on Aug. 4, 1962.
The PEOPLE App is now available in the Apple App Store! Download it now for the most binge-worthy celeb content, exclusive video clips, astrology updates and more!
鈥淚, along with other authors, have said the only thing we can really count on was that they were together at Bing Crosby鈥檚 house that weekend,鈥 says Taraborrelli. 鈥淣ow I鈥檓 saying we can鈥檛 count on that.鈥
鈥淧eople could sneak off,鈥 he adds, 鈥渂ut as I wrote in the book, we don鈥檛 have enough evidence to support that they had an affair.鈥
鈥淭he confusion is that Marilyn had a lot of emotional problems,鈥 he explains. 鈥淚 wrote about them in The Secret Life of Marilyn Monroe, and the problem that historians have faced over generations is that Marilyn told her friends that she and JFK, and she and Bobby, were having affairs. She told people who were close to her this, who then told authors like me. And then you come to realize, Marilyn was not the best narrator of her life.鈥
As for Jackie, he concludes, 鈥漌hat鈥檚 interesting is she didn鈥檛 know if JFK was involved with her or not. She just assumed it. What I do know is after Marilyn died, Jackie was bereft.鈥
He recounts a story told to him by a friend of Janet Rutherford Auchincloss [Jackie鈥檚 half sister] about a conversation [Janet] and Jackie had after Marilyn鈥檚 death.
Janet, who was quite upset, told her sister and her mother, 鈥淭he world destroyed – Marilyn,” he writes. But Jackie didn鈥檛 agree. 鈥淣o, Janet,鈥 she said. 鈥淭he world didn鈥檛 destroy Marilyn. The world built Marilyn up. It was the men in her life who destroyed Marilyn.鈥
Never miss a story 鈥 sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer , from celebrity news to compelling human interest stories.
JFK: Public, Private, Secret comes out July 15 and is available now for preorder, wherever books are sold.