The Proposal star took to on Wednesday (28Oct15) to share the sad news that James C. Reynolds passed away on Sunday (25Oct15) following a 20-year battle with Parkinson's disease. He also asked fans if they could donate to Michael J. Fox's foundation in support of research and treatment of the disease.

"RIP Pops," he wrote. "James C. Reynolds. 1941-2015".

Reynolds opened up about his father's struggle with the disease in an article he wrote for The Huffington Post in 2008. In it he explained his dad's condition had inspired him to take part in the New York City marathon.

"I've watched my father - a strong and proud person who successfully raised (four) arguably insane children - slowly, cruely stripped of his independence," he wrote. "His golden years robbed without explanation. It quite obviously sucks. Witnessing my Dad suffer over the years galvanized my need to step up...

"One of the reasons I chose RUNNING specifically, was because... my competition is the most formidable foe of all; ME. The person I have to beat is the guy I was last week. The person I was yesterday. Indescribably worse, those affected by Parkinson's wage a similar war in their own bodies every single day.

"Unlike a marathon, their struggle won't end in a shallow pool of vomit just outside Tavern On The Green while waiting for an ambulance. They continue day in and day out, silently battling away in the most personal of struggles..."