Princess Diana had a lot of A-list friends in the past, and one of them was Sir Elton John.

In John's new autobiography entitle "Me" released earlier this week, it has stories of his life, his friends and details about his brutal fall out with the Princess.

"She was a very dear friend for years, and then, completely, unexpectedly, we fell out," Sir Elton wrote on his new book. "The cause was a book Gianni Versace put together called 'Rock and Royalty.'"

John explained that Versace's book that was published in 1997 was a collection of portraits by great photographers, including images of big names like Prince and Elton John himself wearing Versace.

The proceeds of the book, according to what John wrote, were going to the AIDS Foundation. Princess Diana agreed to write the foreword, but then suddenly, she got cold feet.

"I think Buckingham Palace did not like the idea of a member of the Royal Family having anything to do with a book that features shots of naked guys with towels draped around them."

John added that at the last moment, Princess Diana withdrew her foreword.

"She said that she had no idea of the book's contents, which just wasn't true since Gianni had shown her the whole thing, and she had said she loved it," Sir Elton John furthered

John then revealed that she wrote back to her, called her and told her how much money she had cost the AIDS Foundation. He also said that the response he got back from Princess Diana was "formal and severe" that the letter started with, "Dear Mr. John."

John later summarized, "And that seemed to be the end of that."

It was only after Gianni's death that they rekindled their relationship. The Princess of Wales reached out to John and reportedly apologized for what she called a "silly falling-out." Princess Diana then asked if they could be friends again.

In an interview with Oprah Winfrey in 1997, John spoke about how he managed to perform a song at the funeral of his friend -- in front of the mourning nation.

Sir Elton John admitted that the mourning "got out of hand" in the aftermath of Princess Diana's death. He admitted that there were good and bad moments; however, in the end, he revealed that he had to listen to Beth Nielsen Chapman songs to cope with the grief. He also shared that he sit in his car and started crying.

 "I had a teleprompter, because I thought, if I'm going to sing this song and I suddenly sing 'Goodbye Norma Jeane,' I'm going to look like an idiot," Elton furthered.

Once the funeral service was done, John reportedly broke down while watching it at home.

Sir Elton John and Princess Diana first met at Prince Andrew's 21st birthday party.

John was hired to play a gig at the party. He showed up early, and when he arrived, the only people he came across were the band and Princess Diana. The two got down on the dance floor at the Charleston, a bonding moment that made them instantaneous friends.

READ MORE: The Surprising Reason Why Kate Middleton Secretly Worked In a Hospital's Maternity Department