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Sir Billy Connolly has noticed a deterioration amid his battle with Parkinson's disease.

The 80-year-old comedian was diagnosed with the brain disorder - which causes uncontrollable movements, such as shaking, stiffness, and difficulty with coordination - in 2013. He revealed that he has been struggling with balance as of late and explained that the "cruel" disease is constantly stopping him from doing things.

He told The Observer: "It’s very difficult to see the progression exactly, because a lot of things come and go. Recently I’ve noticed a deterioration in my balance. That was never such a problem before, but in the last year that has come and it has stayed. For some reason, I thought it would go away, because a lot of symptoms have come and gone away … just to defy the symptom spotters. The shaking has reappeared and the inability to get out of certain types of chairs.

"It’s just added to the list of things that hold me back. I feel like I want to go for a walk, but I go for 50 yards and I want to go home, because I’m tired. I’m being encroached upon by this disease. It’s creeping up behind me and stopping me doing things. It’s a cruel disease."

Billy - who is being cared for by his wife Pamela Stephenson - went on to describe age as a "weird, nasty surprise" as he realises the things he can no longer do.

He added: "It’s a cunning ploy that awaits you. The surprise is f****** nerve-racking. That suddenly you can’t walk any more. Can’t run. Can’t jump. It’s a weird and nasty surprise. I don’t know if we should tell people about it, or just let it be their surprise when they come to it. But I think to prepare for it would be depressing."