Williams, who spent almost four decades behind bars for a crime he didn't commit, has emerged as an early favourite on the show, which begins on Tuesday, and he already has a big fan in Elton.

AGT bosses released Archie's performance of Don't Let the Sun Go Down on Me to tease the new season and Elton was among those floored by his talent.

"I was moved to tears," the rocker said. "The courage and forgiveness shown by him is truly inspiring. The same spirit that the world found so inspiring with Nelson Mandela."

Williams was accused of raping and stabbing a white woman in Baton Rouge, Louisiana when he was 22 and sentenced to life in prison without parole even though he maintained he was at home asleep when the crime took place.

His case was picked up by bosses at the Innocence Project in the mid-1990s, and Archie was finally exonerated by DNA evidence in early 2019 after spending over 36 years in a Louisiana prison.

Meanwhile, AGT judge Simon Cowell was so moved by Williams's story he has agreed to become an ambassador for the Innocence Project, which aims to aid those who have been imprisoned for crimes they did not commit.

"What happened to Archie is tragic," Cowell wrote on Instagram. "While his voice is extraordinary, unfortunately his experience of being sent to prison for a crime he didn't commit is more common than people realise. I'm honoured to become an Ambassador for the @innocenceproject and want to do what I can to help more people like Archie."