Michael J. Fox used anonymous online chatrooms in the late 1990s to secretly gauge how other patients felt about him becoming the high-profile face of Parkinson's disease, he revealed Wednesday to The Hollywood Reporter.

Fox was diagnosed with the condition in 1991 at age 29, but waited seven years before going public. 

Around his 1998 announcement, the "Back to the Future" and "Family Ties" star logged into patient forums to see how people were taking the news. 

When he found near-universal praise, Fox joked to himself, "'Well, f*ck you! I have Parkinson's and you're celebrating.'"

He quickly realized why people were reacting that way.

"I got it. People back then would never in a million years tell you they had Parkinson's," Fox said, noting that his revelation suddenly gave the condition a brave, likable, and resilient public face.

Reflecting on his decision in an interview with the Michael J. Fox Foundation for Parkinson’s Research, Fox said the move came after a long deliberative process.

"A long time ago, when I decided to disclose that I had Parkinson's — and it came after a long deliberative process — I said I need to see where this fits in my world and see how I can use it. And that's what I've done," he said. "As a result, when people see me or talk to me, there is a connection that wouldn't have been there otherwise. There's an understanding."

According to the Parkinson's Foundation, Parkinson's is an incurable, progressive brain disorder that damages dopamine-producing neurons, causing symptoms such as tremors, stiffness, depression, and sleep problems.

The condition affects more than 10 million people worldwide.

Fox has remained open about his health and his mortality. In a 2023 interview with Town & Country, he described his "very complicated" view of the illness.

"I've said Parkinson's is a gift. It's the gift that keeps on taking, but it has changed my life in so many positive ways," he said.

In the same interview, Fox said he isn't afraid of dying. "One day I'll run out of gas," he said.

He expressed a similar sentiment on "CBS News Sunday Morning," saying he does not expect to live to age 80.

"It's banging on the door," he said. "All these subtle ways that get you ... You don't die from Parkinson's. You die with Parkinson's. So I've been thinking about the mortality of it ... I'm not going to be 80."