Former M*A*S*H star Alan Alda has given a rare and poignant update on his decade-long battle with Parkinson’s disease.

Alda said managing the condition had “gone from a part-time job to almost a full-time job keeping track of all these little solutions. But it keeps me always looking for the funny side”.

The six-time Emmy winner and Oscar nominee was diagnosed with Parkinson’s in 2015, but went public about it only in 2018 as his symptoms became apparent.

The 89-year-old also has prosopagnosia, or face blindness, which makes it difficult for him to recognise people. He said life had been a never-ending series of puzzles.

“Almost every day I’m finding a new way to do something,” he told People magazine this week.

“It’s a little like a game. I’ve found whatever the little problem is, if I keep at it, I can eventually solve it, and then I feel like a million bucks. It’s a way to have a good time under poor circumstances.”

But he insisted he was “making progress”.

“I didn’t say in which direction,” he told the magazine, with a grin.

While perhaps most famous for M*A*S*H, Alda has had other notable roles, including in 30 Rock, The Aviator, Crimes and Misdemeanours and Manhattan Murder Mystery.

Nor have his health issues stopped him from acting. He recently had a scene-stealing cameo on Tina Fey’s Netflix series adaptation of his 1981 film The Four Seasons. It follows three pairs of couples as their relationships and friendships evolve over the course of a year.

“I’m so happy for Tina,” Alda said.

“The movie meant a lot to me, and people are reacting to her work very much as they did to mine.”

For her part, Fey is equally complimentary about her costar and inspiration.

Alda played controlling lawyer Jack Burroughs in the original Four Seasons film. The Netflix reboot – which has already been renewed for a second season – features Will Forte in a reimagined version of Alda’s role.

Alda is the father of another character – his Parkinson’s tremors clearly visible while he is on screen.

“He can’t be the same guy – that would break the brain,” Fey said.

“We made him Anne’s dad, and it was a thrill to spend a day on set with him. I was lucky enough years ago to work with him a little bit on 30 Rock. He’s really gifted, has great timing and just came in ready to go.”

In one scene with Fey and Colman Domingo, Alda’s character offers some cheeky marriage advice.

“Every once in a while … [my wife would] say, ‘Congratulations! Take off your pants, it’s a sex day’. You might think of trying that with your spouse,” he says.

Alda famously met his wife Arlene while at college in New York City. At a mutual friend’s party in 1956, they were the only two guests who didn’t hesitate to eat a cake that had fallen on the floor.

“[I knew she was the one] when we ate the cake off the floor,” he said.

“There’s something about flirting over food, and that she laughed at my jokes meant a lot. We still laugh at each other’s jokes a lot, and she’s getting funnier every day.”

The couple have been married 68 years and have three daughters.

Alda said Arlene had also been present for every step of his Parkinson’s battle.

“I don’t have dexterity with my fingers the way I used to, so sometimes she has to tear a package open for me,” he said.

“She’s so good-natured about it. I’m always saying, ‘thank you’. I don’t get proud. I’m glad that I can do something. Proud seems like a waste of time.”

He also looks to Arlene for life advice.

“She always says, ‘the secret to marriage is a short memory’,” Alda said.

“We both try to practice being there when we’re there: Listening, answering, taking an interest. You can get used to somebody, no matter who it is. I’ve always thought if the Pope and Mother Teresa were a couple, after a few years, they’d have to work it out.”

Tina Fey’s The Four Seasons is streaming on Netflix. Alda’s movie version is also available

-with agencies