Australian diver Matthew Mitcham came out as gay before winning a gold medal at the 2008 Olympics, but said Thorpe's enormous fame meant his revelation was unprecedented in terms of the impact it would have.

“There is no precedent, not on this scale,” said Mitcham. “It must have been a very harrowing ordeal.”

Thorpe is among the most successful athletes in Australian history, with five Olympic gold medals. He has been stalked by speculation about his sexuality since he burst on to the international swimming scene when he was just 15.

Mitcham said he believed questions about sexual orientation were not something the media should be asking of athletes who start so young.

“It would have been much harder with people asking continuously, especially when you're just not ready.

“[For athletes in their teens], it’s too young to make a choice, you’re not going to come out and say something that you haven't decided on.”

Almost all gay and lesbian people question their identity, a battle that can take years if not decades, said Mitcham.

He is not surprised that Thorpe denied the claims for so long.

“It took him 15 years to change his answer [to the question of his sexuality], which is a perfect indicator of his struggle,” Mitcham said.

One of Thorpe’s great Australian rivals, Grant Hackett, echoed the calls of support.

“He should be remembered as one of our greatest Olympians,” he told the Nine Network, “Not the guy who came out.”

Sponsorship commitments would have weighed heavily on any athlete deciding whether to go public with their sexuality; the stereotypes and the stigma are well known, said Mitcham.

“That's why we need high-profile gay athletes, to prove the stereotype wrong,” he said. “Thorpe is about as high profile as it gets.

“He’s very influential, I think he has the potential to influence a lot of people, and how people react to it.”

It took another Australian swimmer, Daniel Kowalski, six years after he retired to reveal that he was gay.