Kellie Maloney knew she wanted to be a woman at "three or four years old," she told Good Morning Britain.
As a boxing promoter Ms Maloney, then known as Frank, guided Lennox Lewis to lift the world heavyweight title.
The 61-year-old revealed in a newspaper interview on Sunday that she had been living as a woman for a year and is planning to undergo gender reassignment surgery.
This morning, in her first live television interview, Ms Maloney talked about her life long struggle to come to terms with her identity.
"I didn't like what I saw of myself in the mirror, but I thought it must just be something in my head."
"I feared being seen as a freak, a pervert," she said, "I felt I didn't want to be different."
Ms Maloney told the programme the turning point was when her father died four years ago and "the lid came off the box".
"I think I would have killed myself," Ms Maloney said, if she hadn't come out.
She said her family, including her mother, ex-wife and daughters, have been very supportive.
Ms Maloney hopes to be able to help other people going through the same situation, and has already been asked to speak at a school.