Michael J. Fox was told he would be "pretty much disabled" by now.
The 55-year-old actor was diagnosed with Parkinson's disease - a progressive condition which affects movement for which there is no cure - in 1991 aged 29, but has defied medical predictions and carried on working.
He said: "I was diagnosed 25 years ago, and I was only supposed to work for another 10 years. I was supposed to be pretty much disabled by now. I'm far from it. This is as bad as I get, and I can still go to the store and go marketing."
While his tremors, one of the side effects of the disease, are not as bad as they used to be, Michael still has balance issues from time to time, but it hasn't stopped him working as he starred as Louis Canning in 'The Good Wife' from 2010 up until earlier this year.
He said: "The biggest problem I have now is balance. That's kind of tricky because you fall down a couple of times at 55 and you realise that you're not 25."
The father-of-four's three daughters, twins Aquinnah and Schuyler, 21, and 14-year-old Esmé were all born after his diagnosis, while his son Sam, 27, was born beforehand, and he admits they don't define him simply as someone with Parkinson's.
He added to Haute Living magazine: "I mean, they grew up with this. It's all they know, and I think if you asked them to describe me, the ninth thing they would say would be that I had Parkinson's."
In 2000, the 'Back to the Future' star set up the Michael J. Fox Foundation for Parkinson's Research and since then the foundation has funded an incredible $650 million to research in an attempt to achieve the star's goal of finding a cure for the disease.
The fundraising ideas have included a New York City benefit show in 2013, where the likes of Coldplay performed, and earlier this year the foundation held a raffle to raise awareness of the disease which raised $6.75 million.
The full interview with Michael appears in Haute Living's November/December issue.
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