Vanderbilt says Brando kept a framed picture of himself next to his bed.
She would marry a third time, to director Sidney Lumet, and a fourth time, to author Wyatt Cooper, the man she calls her soulmate.
"Wyatt Cooper was a great love," she said. "We would be married today were he still alive."
The couple had two sons, Anderson and Carter. In 1988, Carter committed suicide, jumping out the family's 14th floor apartment at age 23 as Gloria watched and tried desperately to stop him.
"Had Carter lived, he possibly would have been president today," said Vanderbilt. "He was actually a romantic, he had a Fitzgerald thing, a romantic readiness, and I don't know whether he would have been tough enough for politics, I don't know, but that's what he was interested in."
Anderson would go on to become a popular CNN anchor. Ever the proud mother, Vanderbilt has filled her art studio with tapes of his broadcasts. But what does the famous anchor think of his mother's racy new novel?
"Well," she said, "of course I showed him the book before. I think he thinks, you know, at this point in my life, if I want to write a book, and if it's well written, he's not going to tell me not to. ... He's always very supportive."
Others friends weren't quite so certain of her book.
"I did have two friends who were very Waspy, even more Waspy than I am -- because I don't consider myself Waspy -- that were really concerned," said Vanderbilt, and they said this book is going to ruin your reputation -- so I refrained myself from saying, 'Oh, goody!'"
And that is Gloria Vanderbilt in a nutshell. Approaching 90 fearlessly, in a style that is still uniquely her own.