Sir Billy Connolly has put himself forward to become a stem cell research “guinea pig” as part of efforts to find a cure for Parkinson’s disease.
The Glasgow-born comedian was diagnosed with the illness five years ago.
Now, in extracts from his new book, he says he has been in touch with scientists at Harvard University in the United States, where stem cell scientists are at the forefront of global research into Parkinson’s.
The star poignantly reveals how the incurable illness dominates his life and has forced him to stop shows.
The 75-year-old also tells of his hopes to continue performing.
He writes: “I’ve spoken to guys working on it at Harvard and told them I’ll be a guinea pig for them.
“I think they are going to take me up on that.”
Scientists from Harvard University are collaborating on a two-year study in the race to find a cure for the condition, estimated to affect ten million people worldwide.
Sir Billy, who was knighted last year, has offered himself for the first experimental treatments on humans, which involve engineered stem cells being injected into the part of the brain affected by the condition.
The star was diagnosed with the neuro-degenerative disorder the same week he found out he had prostate cancer, which was later successfully treated with surgery.
Almost five years on, he admits that Parkinson’s is the first thing he thinks about every day. In the book, which is serialised in the Mail on Sunday, he writes: “The thing that I find hardest is coming to grips with the fact that it’s never going to go away.”
He adds: “It’s going to get worse. I try everything. I get massages and do physiotherapy. It helps me and then I get worse again. I have to go and do something else as the disease creeps forward. It seems relentless.”
The comedian has only been on tour once since his diagnosis but his humour remains.
“I wasn’t sure how it [the tour] was going to go because I knew that my body was different, so I thought the best thing to do was acknowledge it.
“I explained that they shouldn’t worry about my left arm, which might creep up until I looked as if I was carrying an invisible raincoat. I was getting the laughs every bit as much as before – maybe even better than before.
“I have come off the road now and I haven’t been playing any shows because of the Parkinson’s, but I would like to do more.”
In the book, Made in Scotland, he discusses his symptoms with Professor Sir Ian Wilmut, the scientist who led the team that created Dolly the Sheep.
Sir Ian, who was diagnosed with Parkinson’s last December, said: “We think we understand enough about what’s causing Parkinson’s and how we can cure it.”
The former shipyard worker also says he has come to terms with the illness.
He writes: “I’m a shadow of my former self. My left arm and left leg aren’t the same as my right any more.
“I’ve learned to take it easier and look out for when the shaking starts. I’m coping with it and I’m hanging in there.
“I don’t know what the future holds but in any case, my doctor said I’d live until I was 90, which is 15 years away.
“I wasn’t expecting to live that long before I got Parkinson’s. I know I’m lucky.”