Ringing in the new year with Rolling Stone Keith Richards on celebrity-packed Turks and Caicos island in 2017, a painful reality dawned on Michael J Fox.
The Canadian-American actor and advocate, who had been diagnosed with Parkinson's disease when he was 29, was on his annual Christmas holiday with his family (and the odd rock star) but was not in the partying mood due to a pinched sciatic nerve.
"It's so painful I can't even walk on the powdery sand without enduring, with each tentative step, a dragon pissing fire down the back of my leg," the 59-year-old writes in his new book No Time Like the Future: An Optimist Considers Mortality.
As the fireworks go off at midnight, he gets a glimpse of Richards' weathered face. "Oh god," he writes. "Keith Richards looks better than I feel". It was at this moment he knew he had see a doctor, quick.
The book - Fox's third memoir following on from Lucky Man and Always Looking Up - contains many moving yet witty anecdotes like this which show his trademark sense of humour, but also the reality of his daily negotiations with Parkinson's disease and having to learn to walk again after spinal surgery.
After cutting short the Christmas holiday, Fox and his wife Tracy, go to see a specialist where they discover he has a spinal tumour - unrelated to Parkinson's disease - which needs to be removed immediately.
Running through the narrative is the drama of the medical madness Fox experiences, and the challenges he faced during rehab only to suffer a devastating fall which nearly causes him to ditch his trademark optimism.
As he writes: "Who am I to think I can accomplish this, when so many have struggled with similar setbacks; some with Parkinson's, some with the aftermath of spinal surgery? I may be the only one who has taken on this particular two-headed beast."
He also manages to convey to readers who don't live with Parkinson's or movement disorders what it feels like to struggle with it every day - particularly after his spinal surgery:
"'Stay inside the frame,' they keep telling me, but as Parkinson's only amplifies, my brain and my body are barely on speaking terms... That's the exhausting part. Every movement, every command, everything that should be a reflex, is a negotiation between Donald Trump and Nancy Pelosi (I don't have to tell you which one is the brain)."
In another chapter, after a particularly grueling rehab session, he compares the slow process of learning to walk again "like being nibbled to death by a duck".
As well as taking the reader through his clinical dramas, Fox - who gained fame playing Alex P Keaton in the sitcom Family Ties and blockbuster movies like Back to the Future - gives an insight into what he calls his 'second' post-retirement acting career which led to eight Emmy nominations.
He talks about how he came to the realisation he still could act in character roles, despite his Parkinson's diagnosis - from eccentric neurosurgeon Dr Kevin Casey in Scrubs and billionaire businessman Daniel Post who has stage-four cancer in Boston Legal to a sex-addicted paraplegic called Dwight in Denis Leary's Rescue Me.
We also learn about how the special bond he shares with his 'rescue' dog Gus (a Great Dane-Lab mix), how he discovered a love of golf at 40, and how he felt when his four children all left the nest.
Throughout the book, as well as sharing personal stories and observations about illness and health, Fox also talks about ageing, the strength of family and friends, and how our perceptions about time affect the way we approach mortality.
From someone who "used to defy gravity on a regular basis and could run like a quarter horse" Fox recalls the times when he was a "perpetual motion machine... constantly running, jumping, hurtling, sprinting, skipping a rope in the boxing gym". This continued as he moved into acting, taking on physical Hollywood roles.
And yet little did Fox know that before he was 30 he would be diagnosed with Parkinson's disease.
"George Bernard Shaw said that youth is wasted on the young," he writes, "but it wasn't wasted on me. I just didn't know that I'd go straight from young to old."
Also in the book, Fox writes about his advocacy work raising global awareness of Parkinson's disease and helping find a cure through the Michael J. Fox Foundation for Parkinson's research, the world's leading non-profit funder or PD science.
In 2006 the foundation donated $800,000 to the University of Melbourne to further their research into Parkinson's disease.
"It's incredible that in less than two decades, The Fox Foundation has funded $1billion in research," he writes.
"One billion dollars is a lot of money, and twenty years seems like a long time, but in research terms, we're high-velocity. In the quest to cure Parkinson's, we're absolutely certain we are the tip of the spear".
Described as a vehicle for reflection about our lives, our loves and our losses, No Time Like the Future is a thoughtful and moving read.
- No Time Like the Future: An Optimist Considers Mortality by Michael J Fox (Hachette), $32.99