Ian Thorpe has revealed that he is gay to Michael Parkinson, in an interview to be screened in Australia on Sunday evening, say reports.
Thorpe tells Parkinson that he is gay, but has dated women in the past, according to Australia's Daily Telegraph.
Parkinson has described the interview, which took place last month and will be broadcast on Australia's channel TEN, as one of the best he has ever done.
"I think his sexuality is no one's business but his own," said Parkinson. "But I think it's one of the best interviews I have ever done in terms of [Thorpe] talking about depression and things like that," he said.
The Olympic swimmers' sexuality has long been a point of speculation.
TEN released a trailer for the interview earlier this week, ending the advert on a cliffhanger and promising that no question would be off limits.
"You've always said that you're not gay, is all of that true?" Sir Michael asks during the trailer. It ends there, and viewers are encouraged to tune into the show on Sunday night.
Thorpe has consistently denied that he is gay. Writing in his autobiography, This Is Me, he said: "I am not gay and all my sexual experiences have been straight.
"The thing that I find hurtful about it is that people are questioning my integrity and what I say. That's the only part I find hurtful, that this is something I would be embarrassed about and that I would hide. ... I try to explain it but I don't know either, but I think it's because I don't fit into the typical stereotype of what a straight athlete would be in the past."
When the trailer was released last week, commentators said that it did not matter whether he was gay or not and many were confused by TEN's attempts to build controversy around the story. After the channel released the advert of Thorpe and Parkinson's interview, many on Twitter lent their support to the Olympic swimmer.
Thorpe, one of Australia's most successful Olympians, has broken 22 world records, won five golds, three silvers and one bronze throughout his career. He also has 10 Commonwealth Games gold medals, 11 World Championship titles, and nine Pan Pacific titles.
Earlier this year, Thorpe was admitted to a rehabilitation clinic after he was found disorientated in a street in Sydney.