Reynolds emphasizes the actor’s significant contributions to those affected by Parkinson’s disease, including his late father.

The 47-year-old shares how Fox played a vital role in supporting his father, James, during his struggle with Parkinson’s.

Ryan Reynolds Says Michael J. Fox Helped His Dad 'Feel Less Alone' in  Parkinson's

“I met Mike 17 years ago,” Reynolds reflected. “I’ve witnessed him elevate the standards for purpose and dedication. It wouldn’t suffice to merely label him as the foremost advocate for Parkinson’s research worldwide. He’s someone who provided solace to my dad, as well as countless others, in their journey.”

“It’d be kinda lazy to simply regard him as a movie star who shaped the lives of people all over the planet with a uniquely electric wit and self-aware charm,” Reynolds continued of Fox. “He’s the sum of these beautiful parts. And so many more.”

Ryan Reynolds praises Michael J. Fox for helping his late father with  Parkinson's 'feel less alone' | Fox News

Reynolds’ father James passed away in 2015 after battling Parkinson’s disease for almost two decades.

The Deadpool star shared that he and his wife Blake Lively named their eldest daughter James after Reynolds’ father. He passed away at 74, shortly after she was born.

“Last year I watched Back to the Future with my 8-year-old daughter,” he continued. “It’s become her favorite film. And for now, that’s enough for me — and her. One more kid from one more generation sees what I saw.”

Reynolds also revealed that James “still has no idea” he and the legend behind Marty McFly are friends.

Ryan Reynolds honors Michael J. Fox for helping people with Parkinson's  disease, including his late father | CNN

“I don’t need to teach my daughter the level of compassion Mike has mastered. Or teach her to tell stories the way Mike tells stories. I need to teach her that it’s OK to fall a lot. It’s the absolute best way to know you’re flying,” he concluded.

While Reynolds’ words are sentimental and heartwarming, he adds a few lighthearted jokes in the essay.

“He [Fox] also falls a lot. Not just because he has Parkinson’s. He falls a lot because he’s unafraid to fly,” Reynolds says of Fox, who has been battling Parkinson’s since 1991.

Since 2009, Reynolds has served on the board of the Michael J. Fox Foundation for Parkinson’s Research, an organization Fox founded in 2000 to help find a cure for Parkinson’s.