Alan Alda reveals he has Parkinson's disease

Alan Alda, the veteran actor and six-time Emmy award-winner, announced Tuesday that he has Parkinson's disease.

Alda -- who starred in the long-running series "M.A.S.H." as beloved combat doctor Hawkeye Pierce -- said in an interview on "CBS This Morning" that he was diagnosed with Parkinson's in 2015.

"I was diagnosed three-and-a-half years ago and I've had a full life since then," the 82-year-old Alda said. "I've acted, I've given talks, I help at the Alda Center for Communicating Science at Stony Brook, I've started this new podcast."

He said he's had hardly any symptoms other than noticing "my thumb twitch."

"I thought it's probably only a matter of time before somebody does a story about this from a sad ... point of view, which is not where I am," Alda said.

Parkinson’s is a long-term, neurodegenerative disease that results in movement-related problems, commonly referred to as "motor" functions. Symptoms can include impaired balance and coordination, slurred speech and difficulty walking.

Alda said he has none of the more severe symptoms many people diagnosed with the disease are coping with daily.

"I'm taking boxing lessons three times a week, I do singles tennis a couple of times a week," Alda said. "I march to [John Philip] Sousa music because marching to march music is good for Parkinson's."

Alda said he also decided to get checked for Parkinson's after reading a health column by Jane Brody in The New York Times that said acting out dreams could be an early symptom of the disease that affects more than 1 million Americans.

"By acting out your dreams, I mean, I was having a dream that someone was attacking me and I threw a sack of potatoes at them," Alda said. "What I was really doing was throwing a pillow at my wife."

He said he hopes to use his celebrity status to spread the word about the disease.

"I'm not angry because it's a challenge," he said. "You know you've got to cross the street. There are cars coming. How do you get across the street? You don't just sit on the pavement and say, 'Well, I guess I'll never cross the street again.' You find a way to do it."

He said coming out publicly about his diagnosis "is going to make one thing a little easier."

"I'm not gonna worry. While I'm trying to say something else, I'm not going to be thinking, 'Is my thumb on a life of its own?' That's just one of the realities of my life. It hasn't stopped my life at all. I've had a richer life than I've had up until now."