Michael J. Fox on Parkinson's disease

Michael J. Fox "can't stop laughing" at the symptoms of his Parkinson's disease.

The Back to the Future actor - who was diagnosed with the condition in 1991 - admits he always sees the funny side of the tremors he experiences, particularly when he's trying to do something kind like make coffee for his wife Tracy Pollan.

He told AARP The Magazine: "The truth is that on most days, there comes a point where I literally can't stop laughing at my own symptoms.

"Just the other morning I come into the kitchen.

"I pour a cup -- a little trouble there. Then I put both hands around the cup. She's watching. 'Can I get that for you, dear?' 'Nah, I got it!'

"Then I begin this trek across the kitchen. It starts off bad. Only gets worse. Hot java's sloshing onto my hands, onto the floor."

Though the 55-year-old star admits his symptoms can be distracting, he is thankful "none of them hurt".

He added: "The only real pain I get is in my feet, which sometimes shuffle and curl up in cramps when I'm sleeping.

"Which is why I keep a very stiff pair of shoes on the floor next to my bed."

Michael went public with his diagnosis in 1998 and he admits he eventually started to laugh at the way people looked at him with "dread". 

He said: "It was easy for me to tune in to the way other people were looking into my eyes and seeing their own fear reflected back.

"I'd assure them that 'I'm doing great' -- because I was.

"After a while, the disconnect between the way I felt and the dread people were projecting just seemed, you know, funny."

The former Good Wife actor recalled being reduced to tears when boxing legend and fellow Parkinson's sufferer Muhammad Ali - who died last year - called him to offer reassurance about their shared battle.

He said: "In this raspy, paper-thin voice, he said, 'Aahhhhh ... Michael, now that you're in it, we'll win this fight.'

"What could I say? Sitting there alone listening to Muhammad Ali, this giant -- I was welling up, almost openly weeping."

This article originally appeared in NZ Herald and is published here with permission.