Michael J Fox says he tries to use his dark sense of humour while battling Parkinson’s disease – but admits it’s not always easy.

The 63-year-old actor was diagnosed with the disease, which causes uncontrollable movements, such as shaking, stiffness, and difficulty with balance and co-ordination, in 1991.

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.

“It’s hard for me. But I gotta keep it intact,” he told People.

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 $US2 billion ($3.1 billion) worth of research.

At the foundation’s annual gala on Saturday night (US time), stars such as Stevie Nicks arrived to show their support.

“I can’t believe – a lot of these people I’ve known for years and years, they’re so kind to me,” Fox said.

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

Last year, Fox’s foundation announced a major breakthrough in its quest, when its researchers successfully trialled a test that can accurately detect a biomarker for the disease in people that haven’t as yet developed symptoms.

A “deeply moved” Fox described the breakthrough at the time as “huge”.

At the same time, the former Family Ties star said he’d had a “terrible year”, suffering numerous broken bones in a fall.

Fox married his Family Ties co-star Tracy Pollan in 1989. They went on to have Sam, 35, twins Aquinnah and Schuyler, 25, and Esmé, 23.

He recently admitted his “biggest goal” in life was to have a family and he was open to the idea of acting but was more focused on his campaign work.

“My biggest goal, I think, was to raise a family. We have four amazing kids and that’s been the big thing,” Fox told Entertainment Tonight.

“Then the other is with the foundation. If someone offers me a part and I do it and I have a good time, great.”

Fox wowed the crowd at Britain’s Glastonbury Festival earlier this year. He joined rockers Coldplay on stage to play guitar in their hit Fix You.

-with AAP