Stepping out for the final song of his last ever Las Vegas show with sister Marie, Donny Osmond knew immediately something was wrong.

“I couldn’t feel my arms, then suddenly my legs too,” he says. “I didn’t tell anyone what was happening to me......I just kept dancing and finished the show.”

For the thousands of fans packed into the audience at the Flamingo Hotel to witness the end of Donny and Marie’s 11-year residency in Sin City, they were none the wiser.

But that moment in November, 2019, set in motion the wheels of a 12-month nightmare that marked one of the most challenging moments in singing legend Donny’s 60-year career.

Doctors found that his spine had shifted due in part to previous dancing injuries, including one sustained when he won the US version of Strictly Come Dancing, in 2009.

Subsequent back and neck surgery was a success, but Donny wasn’t prepared for what happened next as he recovered at his home in Utah.

“I thought everything was going to be fine, but it couldn’t have been worse,” he says. “I got a secondary infection which meant I wasn’t able to move.”

Donny endured months and months of rehab to try and get on his feet unaided again, relying on a walking frame just to hobble around.

Asked if he was worried if he would never be able to walk again, he says: “ Oh sure, absolutely. It absolutely crossed my mind. But I just didn’t take no for an answer.”

As well as assembling a crack team of “great professionals” to try and get his body moving again, Donny also credits his strong Mormon faith as being central to his recovery.

“It was my faith, a lot of hard work and positive thinking,” he says.

Throughout the ordeal, he had the support and love of his wife of 43-years Debbie by his side, with whom they have five sons and 12 grandchildren.

“She knows exactly the sort of determination that I have and she knew I would be fine,” he says.

Slowly, but surely, he managed to walk again over the course of several months.

He even laughs as he says the ordeal was in some ways a “blessing in disguise” as not being able to walk – or really do anything – meant he just retired to his home studio.

“It enabled me to focus on my lyrics and focus on a new record,” he says.

Incredibly, these dark times coincided with some of the best music he has ever made.

His new album – Start Again - is the first he has entirely co-written and produced, with the first single Who soaring to the top of the iTunes chart.

And it’s only after you learn of his battle to walk again, do you realise how the music video for Who – in which Donny dances around – must have meant a lot to him.

“I made the video about a year and two months after it all happened,” he says. “Oh my goodness, just to get back to walking, let alone dancing, was really something.”

Such has been his recovery he has now landed a new solo Vegas residency at Harrahs where he sings – and dances – several times a week.

“Last night’s show was wild....the amount of dancing and singing and everything,” he says.

“I started from below ground zero but it feels like coming back from the dead. I’m pain free now, maybe even stronger than I was before.”

It’s little wonder Donny was able to pick himself up off the floor after an amazing career in which he has been forced to constantly reinvent himself.

Bursting onto the scene aged just five alongside his brothers in The Osmonds, Donny soon stole the show and became a solo star, singing hits such as Puppy Love with doe eyes which won him legions of teenage fans.

By the time he was 17, he’d had 12 top 40 hits, either solo or with his brothers.

But his career hit the buffers when he hit his 20s, with his fans all grown up, and he found himself in the wilderness.

To make matters worse, his family had lost close to £50million through bad financial planning. A 1982 Broadway show Donny starred in closed after only one performance.

But he says these hard knocks – and the stinging words of his critics - hardened him up to deal with whatever life threw at him.

“I mean, I still quote Rolling Stone magazine when they say the worst day in rock and roll history was the day Donny Osmond was born,” he says. “It killed me at the time, but it was probably good for me because it really built up some calloused skin on me because I relaised you can’t please everyone.”

It wasn’t until 1989 when Donny’s promoter released Soldier Of Love - without revealing Donny as the singer as he feared fans would be put off - when things took off again.

It was a massive surprise hit and, after his identity was revealed, Andrew Lloyd Webber cast him as Joseph in Joseph And The Amazing Technicolor Dreamcoat on Broadway.

Suddenly Donny never looked back. A winning turn on Dancing with the Stars followed, as well as the small matter of selling more than 100million albums.

His latest is , amazingly, his 65th. He’s even coming to the UK this Christmas to star in Pantoland at The Palladium.

“Those British fans have always been so loyal to me,” he says.

Throughout the ups and down has been wife Debbie, who Donny met when she was a cheerleader at high school.

“People have said I robbed the cradle and I was still in it,” Donny laughs. “She was dating my brother and I kind of moved in and took over. I just fell in love. She was my best friend before she was my lover. And we just connected on so many levels.”

And there have been other solid friendships along the way, including fellow child star Michael Jackson. The pair struck up an instant connection.

“We related on so many different levels. I remember him saying to me, he said, “Donny, you’re the only person that really knows what my childhood was like.” And he said, “And I’m the only person that really knows what your childhood was like.”

He laughs as he remembers the pair of them donning trench coats and wigs to go to the cinema together in disguise.

“We were just kids...I am sure people knew who we were anyway,” he says.

But Jacko was also on hand to offer some tough love.

“Just as Thriller was kicking in, I said, ‘Mike, how do I get back on the charts?’ And the first thing he said, ‘well you’ve got to change your name, your name’s poison.’

"Which hurt. But it was true. He then said I needed to be true to myself and I’ve never forgotten that. This album is what I want to be. This really shows who I am.”

• Donny’s new album Start Again is out now via BMG
• Pantoland at The Palladium runs from 4 December 2021 until 9 January 2022