Ryan Reynolds has paid tribute to "incredible" Michael J. Fox.
The 'Green Lantern' actor struck up a friendship with the 'Back to the Future' star - who suffers from Parkinson's disease - five years ago when he ran the New York marathon in aid of Michael's charitable foundation, and says his pal is "unsinkable".
He said: "He's incredible in everything that he does, from the foundation to his work to his work ethic.
"There's a reason why everyone likes this guy so much - he's just unsinkable."
Both Ryan and Michael were brought up in Vancouver, Canada, and the 'Croods' star says it has given them a "shared connection".
He said: "I've gotten to know his family over the years and they're just amazing. They're just an incredible lot of people."
"We have that connection - we're all from the same part of the world,"
The 37-year-old star's father also suffers from Parkinson's disease - which causes degeneration of the nervous system, often causing involuntary tremors and muscle spasms - and the actor is grateful for the help he receives from the Michael J. Fox Foundation for Parkinson's Research.
He told People: "My dad's hanging in there. Like so many people who are afflicted with this disease, they have an incredible resource in this foundation ... They also have a reason for hope."