Michael J. Fox tries to keep his sense of humour "intact" amid his Parkinson's battle.

The 63-year-old actor was diagnosed with the disease - which causes uncontrollable movements, such as shaking, stiffness, and difficulty with balance and coordination - in 1991 and when asked about how he copes, he admitted that while it is "hard" for him to laugh, he has to try to find the fun in things.

He told People: "It's hard for me. But I gotta keep it intact."

In the years since his diagnosis, the 'Back to the Future' star has established the Michael J. Fox Foundation - which is dedicated to finding a cure for Parkinson's and has gone on to fund $2 billion worth of research - and upon its annual gala, stars such as Stevie Nicks arrived to show their support.

He said: "I can’t believe — a lot of these people I’ve known for years and years — they’re so kind to me.

"I think because they see an opportunity for a win, for a big advancement, and that’s what we’re working toward."

The former 'Family Ties' star - who married Tracy Pollan in 1989 and went on to have Sam, 35, twins Aquinnah and Schuyler, 25, as well as Esmé, 23, with her - recently admitted that his "biggest goal" in life was to have a family and that he is open to the idea of acting but is more focussed on his campaign work.

He told 'Entertainment Tonight': "My biggest goal, I think, was to raise a family. We have four amazing kids and that's been the big thing. And then the other is with the foundation. If someone offers me a part and I do it and I have a good time, great."