Most decorated Olympian Michael Phelps' self-proclaimed girlfriend has come out with a shocking revelation, saying that she was born intersex and lived as a boy until her teens.

Taylor Lianne Chandler posted on her Facebook page that he birth name was David Roy Fitch and was born with male genitalia with no testicles, but also had uterus and no ovaries, News.com.au reported.

She said that she decided to change her name as a teenager and later underwent surgery to become a woman and even claimed that the 29-year-old Olympian was unaware that she was born intersex and that she did not tell him during their relationship.

The alleged couple also have a bit of an age gap between them, and Phelps is 29 and Chandler is 41-years-old.

Chandler, who dated the swimmer before he checked into rehab in September, said that she met Phelps on hook-up app Tinder and the pair met up at the Olympian's Baltimore home to watch a football game.

The 41-year-old said that one thing led to the next, and they made love during halftime, and that later they had sex again.

She also described her 'amazing intimacy' with Olympic swimmer and it was the first in her life that someone made her feel like a true woman.

As she explains in a Facebook post, 'I was never a man, never lived as a man. No one can say they knew me as a man or produce a photo of me as a man.'

Phelps with Olympic 22 medals, is currently serving a six month suspension from swimming as a result of his DUI.