Michael J. Fox and wife Tracy Pollan celebrate their 35th wedding anniversary

Michael J. Fox and Tracy Pollan have celebrated their 35th wedding anniversary.

To mark the occasion, the pair shared tributes to each other on their respective Instagram pages.

"35 years!!! Happy anniversary my love," 63-year-old Pollan wrote in the caption of her post.

"Here’s to many more glorious adventures together. I could not love you more."

The Back to the Future star commented on his wife's post, saying: "Likewise, so beautiful just like you. Happy Anniversary!"

Fox then shared his own tribute on his page.

"35 years of laughter, living, listening and loving you @tracy.pollan. Thank you for it all. Forever yours, Mike," he said.

The couple first met on the set of Family Ties.

Fox played Alex P. Keaton on the hit sitcom and Pollan played his girlfriend, Ellen. They were both dating other people at the time but became friends.

They later reunited on the set of 1988's Bright Lights, Big City and began seeing each other romantically. They married that year after seven months of dating.

In 1991, Fox was diagnosed with Parkinson's at the age of 30. The news sent him into a self-destructive, alcohol-fuelled stupor.

He woke one morning on the couch, a bottle of spilled beer soaking into the carpet, his toddler son fussing around him. An exhausted, 'overwhelmed' Pollan was on her way out the door for work, but in that moment contemplated leaving for good.

"She took in the scene and simply asked me, 'Is this what you want?'" Fox recalled in his memoir.

He never drank again.

The couple went on to have three more children, all of them girls.

Fox enjoyed a 103-episode run on the political comedy Spin City, before leaving to focus on his Parkinson's research charity, The Michael J. Fox Foundation.

The former actor doesn't know how many years he has left, or when his disease will progress onto the final stage.

But he plans to stay optimistic and bring awareness to Parkinson's in the hope that a cure can be found.

"I've had Parkinson's for 100 years and I've made peace with it. We started a foundation literally from nothing. We're responsible for 17 active therapies that we now use, that were never thought of before - we funded a billion dollars in research," he said to Today.

"Optimism is a choice but in a way it isn't. I don't think there is another viable choice than to hope for the best and work towards it."