It came as a hammer blow to the world of showbiz and his army of fans across the globe.

Sir Billy Connolly was diagnosed with Parkinson’s disease in 2013 and, five years later, announced his retirement from the live performance circuit which had made him a household name.

“It doesn’t roll the way it used to,” the Glasgow-born comedy icon said a few months ago.

“I would phone home to my daughter, to my wife and say, I can’t think of anything funny. Can you think of anything funny I’ve said in the last couple of days?”

But now the 78-year-old has said he feels “happy in his skin” after making the “obvious” decision to step back from performing. Sir Billy, known affectionately as The Big Yin, said being knighted in 2017 for services to entertainment and charity had offered him the “full stop” he needed to make the decision.

Speaking about a new show looking back at his career, he said: “It’s been nice, it’s funny talking about the end of my career, because I’ve given it up and it’s strange talking about it as a thing of the past.

“It’s nice to come to that conclusion myself, that I should stop. It’s a nice, healthy feeling.”

On his decision to retire, he said: “It was obvious. I had done everything I wanted to do, and I’ve got this Parkinson’s and I don’t want to be on stage with Parkinson’s. And that’s the end of it.

“And it’s a natural end because I’m dead happy in my skin. I had a nice career, I did rather well, and I got knighted and that’s like the full stop.”

Sir Billy was famous for his energetic presence on stage. Symptoms of Parkinson’s disease include decreased mobility and difficulty speaking, leaving him unable to perform as he had in his pomp. But the performer said he did not worry about the increasing impact the disease had on his life.

He said: “It’s there and I just deal with it. “I don’t go to meetings with other Parkinson’s people and talk about it. I just get on with it.

“I get invited all the time to these Parkinson’s society things, to come and have lunch on a Wednesday and talk about Parkinson’s. I can’t imagine anything more awful.

“I went one day with my son and we were having lunch and it was less than great. Talking about Parkinson’s, it’s depressing. It’s just a fact of life, it’s in me and I deal with it.”

Previously a vocal opponent of Scottish independence, Sir Billy announced his support for the movement following the 2016 Brexit referendum. The Florida resident also said he thought Scotland was moving towards leaving the union.

He said: “I think they’re getting close to it. They’re fed up with the voting one way and getting whatever England votes for.

“And when they tried to vote for independence, the English Government said it’s bad because you’ll lose the common market, you won’t have the European market because you’ve gone independent.

“And so they voted against independence and then this Government voted to leave the common market, so they felt cheated.

“I don’t know if they’ll ever do it, but I think that’s the way they’re heading.”

Billy Connolly: It’s Been A Pleasure airs on ITV on Monday December 28.