Thorpe, who had long denied that he was gay, told British talk show host Michael Parkinson in an interview broadcast on Australia's Channel 10 that he just recently realized the truth about himself. (Agencies)
"I'm not straight," Thorpe said.
"And this is only something that very recently â€” we're talking in the past two weeks â€” I've been comfortable telling the closest people around me exactly that,” he added.
For years, Thorpe took great pains to hide his sexuality. In his 2012 autobiography, "This Is Me," Thorpe wrote, "For the record, I am not gay and all of my sexual experiences have been straight. I'm attracted to women. I love children and aspire to have a family one day."
Thorpe, 31, said being asked about his sexuality by journalists when he was just a teenager forced him to adopt a defensive attitude toward the issue.
He was too young to know whether he was gay or straight, and said he responded that he was straight to avoid teasing from classmates but things spiraled from there.
"I felt the lie had become so big that I didn't want people to question my integrity," he said.
"And a little bit of ego comes into this; I didn't want people to question ...have I lied about everything?” he added.
Now, he says, he wishes he had come out sooner.
"I'm comfortable saying I'm a gay man," he said.
"And I don't want young people to feel the same way that I did. You can grow up, you can be comfortable and you can be gay,” he added.
Part of his reluctance to come out, he said, was fear of letting his family and his fans down.
"I wanted to make my family proud. I wanted to make my nation proud of me. And part of me didn't know if Australia wanted its champion to be gay," he said.
"But I'm telling not only Australia, but I'm telling the world, that I am,” he added.
Thorpe added that he is looking forward to living his life openly without the burden of carrying a secret. He wants to find a partner he said and start a family.
Thorpe retired from swimming in 2012 after winning five Olympic gold medals, three silvers, and one bronze and setting 22 world records.
Thorpe, who had long denied that he was gay, told British talk show host Michael Parkinson in an interview broadcast on Australia's Channel 10 that he just recently realized the truth about himself.