The rumoured girlfriend of the most successful Olympian of all time Michael Phelps has revealed that she was born intersex.

Taylor Lianna Chandler wrote a lengthy Facebook post detailing that she was given the name David Roy Fitch at birth, but had both female and male genitalia.

Chandler, who revealed that Phelps is unaware of her former identity, wrote: "By the time I could walk and talk I made it clear I was a girl and dressed as one. In my early teens I was medically diagnosed and went on testosterone blockers, at 15 estrogen enhancers. My birth certificate was modified along with my name while I was a teenager, prior to any corrective surgery."

Phelps's self-proclaimed girlfriend has also expressed her fears that the American swimmer will end their relationship due to her revelation and his position in the public eye.

The 29-year-old has recently been involved in a treatment programme at a rehab facility after he was charged with drink-driving.

Chandler added: "I am probably going to lose him because he is a brand that his team wants to protect and things since he went to rehab came to my attention that didn't put him or our relationship in the best light. He is the first man I ever had intimacy with and felt comfortable and all woman.

"When he went to rehab I had to go through all this scrutiny and tabloid mess by myself. His team at Octagon abandoned me, whether he knows that or not I do not know."

Phelps has put his return to professional swimming on hold after deciding to go to rehab.