Carly Simon Opens Up on Unlikely Friendship with Jackie Kennedy — and Jackie's Thoughts on JFK, Aristotle Onassis & More

Carly Simon, who was friends with Jacqueline Kennedy Onassis for the last decade of her life, chronicles their surprising relationship in Touched by the Sun: My Friendship With Jackie. The memoir, which will be published on Oct. 22, is filled with captivating anecdotes about the former first lady: her wit, how she felt about both of her husbands (President John F. Kennedy and Aristotle Onassis) and her children and her sense of humor and her fragility.

“I could be neurotic, bohemian and all over the place; she always had to be so correct,” the “You’re So Vain” singer, 74, says of Jackie in an exclusive interview in this week’s issue of PEOPLE. “I was who she wasn’t. I think she got a big kick out of that.”

Jackie’s son John F. Kennedy Jr. introduced his mother to the singer on Martha’s Vineyard in 1983, and the two women were drawn to each other. They remained friends until Jackie’s death in 1994 at 64 years old.

It took years for Simon to decide to write a book about her bond with the revered presidential widow.

“Why am I writing about someone so private who disliked attention?” she asks, anticipating the question. “If someone affects your life as Jackie did mine, you can’t not write about her.” (Also, she adds, “I withheld a great deal.”)

• For more on Carly Simon’s surprising, enduring bond with Jacqueline Kennedy Onassis and the memories they made together, subscribe now to PEOPLE or pick up this week’s issue, on newsstands Friday.

Stephen Rose/Getty
Stephen Rose/Getty
Carly Simon | Liz Linder
Carly Simon | Liz Linder

As the women got to know each other, Jackie, who was 16 years older and intensely private, began to share confidences.

Jackie talked to Simon about President Kennedy’s adultery. She “understood that he made some stupid mistakes,” Simon says, but Jackie brushed off the affairs because “she knew he loved her more, much more.”

She also spoke about her second husband, Onassis, whom she married in 1968, five years after the president’s assassination.

RELATED: Carly Simon Remembers the ‘Surreal’ Scene Near Jackie Kennedy’s Death Bed: Laughter, Singing and Goodbyes

“She said he was very sexy — he would sing to her on his yacht and take her great places to make love,” Simon recalls. “She knew marrying him was the bad-girl move. In a way I never knew whether she was sticking up for her own decision or whether she really loved him.”

Always protective of her two children, John Jr. and Caroline, Jackie also shared her concerns about her son.

RELATED VIDEO: JFK’s Daughter Caroline Gave a Reading at Family Wake & Mass for Saoirse Kennedy Hill

Jacqueline Onassis Kennedy in 1993 | John Tlumacki/The Boston Globe/Getty
Jacqueline Onassis Kennedy in 1993 | John Tlumacki/The Boston Globe/Getty

“Jackie was very consumed with getting him on the right path,” Simon says. “She didn’t approve of some of [the women] — she was horrified by Madonna.”

While the friends shared some very serious moments, Simon explains that Jackie was also “incredibly funny.”

RELATED: Inside the ‘Flirtation’ Between JFK Jr. and Madonna — ‘She Was Irreverent and He Liked It’

In 1990, they attended a recording session with opera singer Plácido Domingo. The next day, Simon says she got a gushing letter and photograph from him. But when Simon called Jackie to tell her the news, the older woman wasn’t surprised.

“She paused for a long time, and then she said, ‘Carly, did you really think it was from Plácido?’ ” Simon says. “She’d written it herself and disguised her handwriting! The practical joker in her was nonstop.”