EXCLUSIVE: The Shocking Sex Secret Cher Left Out of Tell-All Memoir: How Diva Had a Romance With Her Mother's Best Friend… When She Was Only 14

The shocking allegation was first included in Lawrence Qurik's book, Totally Uninhibited: The Life and Wild Times of Cher.

In the book, it claimed that when Cher was just 14 years old, she was allegedly in a yearlong sexual relationship with a man who was 35 years old — and her mother's best friend.

According to Qurik, Cher allegedly didn't tell her mother, Georgia Holt, about the affair until many years later due to the shocking age difference.

A friend claimed that the singer's sexual activities were "ultimate acts of rebellion in her troubled relationship with her mother."

The pal added: "Cher felt a need to complete."

Following the rumors, Cher opened up about the alleged affair.

The singer said: "He was a great guy. He was handsome. He was a best friend of my mother's. This guy was a 10. He looked like Tom Selleck, but blond. Six-foot 4. He made the women crazy. He loved them. He left them."

She explained that the affair started after he was painting a staircase in her house and he allegedly "kissed" her.

Two weeks later, Cher explained that he returned to their home and sat on her bed when she was asleep.

Cher claimed that she was "with him for a year" and she "wanted to be close with him."

The singer continued: "The idea of being passionate to sleep with him, that way I was passionate about sleeping with Rob (Camilletti) absolutely didn't exist for me. With this guy I would really have enjoyed kissing him as much as having sex. I don't think you know what good sex is at 14 and a half."

Cher's mom was a beauty pageant winner and married eight times — which allegedly was a driving force behind the singer's rebellious ways.

The friend explained: "There was no need for Cher to compete. She was loved as much as her sister. But the uncertainty came from within her."

On November 19, Cher released her bombshell memoir that included other shocking stories about her childhood — including losing her virginity at 14 years old.

The now 78-year-old singer said she had "revenge sex" with a boy after he treated her "like an embarrassing kid."

She wrote: "I had never wanted to, otherwise I would have done it one of the five hundred other times he asked. But I was so angry at being dismissed, I decided to, if not lose, loan out my virginity to him."

Cher called it a "massively overrated experience" and wrote: "I asked him, 'Is that it? Are we finished?' Then I told him to go home and never come back. I wanted him to feel just as dismissed as he’d made me feel."