BELOVED American actor and director Alan Alda, who played Hawkeye Pierce in the iconic long-running war TV series M*A*S*H, has revealed he has Parkinson’s disease.

The six-time Emmy Award winner said he was diagnosed three-and-a-half years ago. Alda, 82, told CBS News: “I’ve had a full life since then. I’ve acted, I’ve given talks, I help at the Alda Centre for Communicating Science at Stony Brook [University in New York].

“I started this new podcast. And I noticed that — I had been on television a lot in the last couple of weeks talking about the new podcast — and I could see my thumb twitch in some shots and I thought, it’s probably only a matter of time before somebody does a story about this from a sad point of view, but that’s not where I am.”

Alda said he was not angry over the diagnosis, and is instead viewing it as a challenge. He told CBS he thought that revealing his diagnosis might be helpful to others with Parkinson’s disease that there are things they can still do, encouraging them to “take action”.

“If you get a diagnosis,” he wrote on Twitter, “keep moving!”

Alda later reiterated, again via Twitter, that he is in good health.

“I take boxing lessons three days a week, play singles tennis twice a week, and take a mild pill — all Dr. recommended. I even juggle a little. And I’m not entering dementia. I’m no more demented than I was before. Maybe I should rephrase that,” the star wrote.

“Really, I’m good.”

Parkinson’s disease is a nervous system disorder that affects movement and causes tremors.

Actor Michael J. Fox was diagnosed with the disease at age 29, and singer Neil Diamond, shared his diagnosis earlier this year.

Alda said he asked his doctor for scans after he started “acting out” his dreams, which he had read was an early sign of the disease.

“I was having a dream that someone was attacking me and I threw a sack of potatoes at them, but what I was really doing was throwing a pillow at my wife,” he told CBS.

“I didn’t have any (other) symptoms, the doctor said, ‘Why do you want a scan? You don’t have any symptoms,’ and I said, ‘I want to know if there’s any I can do, I want to do it before things start to show up.”

Alda also sent a message to his fellow sufferers.

“This is not to short-change people who are suffering with really severe symptoms,” he said. “But in the very beginning, to be immobilised by fear and think the worst thing has happened to you, it hasn’t happened to you, you still have things you can do.”

Alda played a senator who ran for president on The West Wing and he also hosted Scientific American Frontiers on US television network, PBS.