The co-creator of the Vicar of Dibley has jokingly thanked his 2011 Parkinson's diagnosis for providing the subject matter for his first-ever feature film.
Onwards and Sideways was written by Paul Mayhew-Archer and is based on his experiences of living with the debilitating disease for the past 15 years.
It follows Emma, played by Laura Linney, and Rhys Ifans's Tony as they navigate the five years after they are diagnosed with Parkinson's on the same day.
Mayhew-Archer, who lives in Oxfordshire, said ahead of its release on Friday he had "always wanted to write a film" but "never had a subject until I got Parkinson's".
"I remember there was a moment in my first meeting with a neurologist who said to me 'your facial muscles are somewhat frozen, you seem to be finding it quite hard to smile'," he recalled.
"And I heard myself saying, 'well, it could be because you've just told me I've got Parkinson's'."
That, he said, was "the moment I realised that I was going to try and deal with this thing through laughter and comedy and gently ribbing this monster of an illness".
Explaining the plot of the film, Mayhew-Archer said it centred on two people, played by Linney and Ifans, diagnosed with Parkinson's on the same day.
"They've also been told that they can expect five good years - which is what I was told - so the plot then follows those five years," he said.
But he said the feature was "not just about Parkinson's, it's about hope, about determination and about love".
Alongside its star-studded cast, it has been directed by John Madden - best known for his Academy Award Best Picture-winner Shakespeare in Love.
"They're just fantastic people, they were all our first choices," Mayhew-Archer said of the cast and crew.
He has also found a part for himself in the film, describing his character as "an old miserable bloke who complains all the time".
"I've given myself many of the funniest lines," he said.
Ahead of its release, the film has garnered a warm reception from critics and had a perfect 100% rating on the review aggregator Rotten Tomatoes.
It premiered at the Toronto International Film Festival in September - where it was followed by a lengthy standing ovation by the audience.
"I think at the time it was rather insensitive of them to give me a standing ovation since I was in a wheelchair," Mayhew-Archer joked.
"But it was it was an amazing thing."
The BBC-commissioned film opened in cinemas across the UK, including Mayhew-Archer's local one in Abingdon, on Friday.
"This is one of the best weekends of my life," he said.
"I have to thank Parkinson's, thank God for that illness, because I would not have had these experiences without it.
"My whole message is embrace life and look forward to the good things - find the challenges that you can overcome and experience things that are fun."
Onwards and Sideways was released in UK cinemas on Friday, and will be on BBC One and iPlayer later this year.
