Olympic champion Thorpe to come out: Reports

After years of speculation about his sexuality, five-times Olympic champion Ian Thorpe will reveal he is gay in a tell-all interview on Australian television later on Sunday, local media reported.

The 31-year-old will make the admission to British interviewer Michael Parkinson on Australia's Channel 10, the Sunday Telegraph reported.

A 25-second teaser clip of interview showed Parkinson asking Thorpe directly if he was gay, though Australia's most decorated swimmer did not answer question in the snippet.

Thorpe has constantly denied he was gay and wrote in his 2012 autobiography 'This Is Me' that he was heterosexual.

"For the record, I am not gay and all my sexual experiences have been straight," Thorpe wrote in the book. "I'm attracted to women, I love children and aspire to have a family one day.

"I know what it's like to grow up and be told what your sexuality is, then realising that it's not the full reality. I was accused of being gay before I knew who I was."

Thorpe has had a torrid past 12 months, battling depression and an infection he contracted following shoulder surgery that required hospitalisation in April.

At the time his agent said he was unlikely to swim competitively again. He had retired in 2006 then attempted a comeback in 2011 to try to make the 2012 London Olympics.

Earlier this year he was admitted to hospital to treat depression after he was found disoriented in Sydney and police were called.

Parkinson told the newspaper the interview was one of the best he had conducted in his storied television journalism career as Thorpe also details his battles with depression.

"I think his sexuality is no-one's business but his own," Parkinson was quoted as saying.

"But I think its one of the best interviews I have ever done in terms of (Thorpe) talking about depression and things like that."