The 74-year-old singer and author discussed her friendship with Jacqueline Kennedy Onassis during Tuesday's episode of Today following the release of her book Touched by the Sun: My Friendship with Jackie.
Simon and Onassis first met in 1983 while Onassis, then 54, was working as an editor at Doubleday publishing company. Onassis wanted Simon, then 38, to write a memoir, but the singer demurred and asked to write children's books instead.
Onassis agreed, and Simon wrote two children's books for Doubleday. The collaboration marked the start of Simon and Onassis' unlikely friendship, which lasted until Onassis' death from cancer at age 64 in 1994.
"[Onassis saw in me] something that she wanted to have a little bit of herself," Simon said. "A free spirit, who had the license to be, in a rock and roll kind of way, loose as a goose. I could smoke a joint if I wanted to, and she didn't have the license to be free."
"She was a naughty girl and she liked that in herself and she like that in other people," she added.
Simon recounts other details about her friendship with Onassis in Touched by the Sun, published Tuesday. She said on Today that she never contacted Onassis' daughter, Caroline Kennedy, about the book.
"I thought about it often, and I thought, 'Oh, I'll wait until it's finished. If she objects to anything, I'll remediate.' But I never did call her," Simon said.
Simon said she believes Onassis would have approved of the book, despite being a very private person.
"She would have been very interested in herself. That goes along with her first mandate to me, which was to write a memoir about the interesting people that I knew. What better answer than to write about Jackie," she said.
Simon remembered Onassis as "a most extraordinary and fascinating beautiful woman" in an Instagram post about Touched By the Sun in August.
"Jackie was so feminine but she was immensely gutsy and smart and I loved writing about her and remembering so many of our interactions," she wrote. "She was a wonderful friend, a great lady whose light was so bright as to light up the sky. I called the book Touched By The Sun for that very reason."