It was always going to be a tough sell: "To make people believe that someone in a wheelchair who can barely move or talk could be as exciting as a guy in tights swinging down Madison Avenue in a superhero costume… it's a lot of money on the table."
Or so The Theory Of Everything's screenwriter Anthony McCarten puts it.
But find the money he did - all US$15 million (S$20 million) of it - if out of his own pocket initially.
"I felt compelled to get the rights and no one else was gonna help me do that, so I did it. It's like starting a benign religion and standing on a soapbox. Most people just walk past you and think you're a crazy guy," the screenwriter and novelist tells Life! at a press event in London recently.
Still, he had a secret weapon. Enter the unlikely rock star for a hero's life story: the world's most famous living scientist, Stephen Hawking.
Call it then, if you must, an investment in time - of McCarten's patience and the Cambridge don's physics.
"It's almost an antidote to the big Hollywood fairy tale," McCarten, 53, says.
"There's certainly a new audience for sophisticated adult movies… It's an older audience that is now going to the movies again - in big numbers."
In its finished version, the 123-minute feature film recounts the unusual life and loves of the severely disabled godfather of theoretical physics, based on a memoir by his ex-wife, Jane Wilde.
Opening in Singapore theatres tomorrow and directed by James Marsh, 51, the movie stars rising English actors Eddie Redmayne and Felicity Jones.
With emerging talk of potential Oscar nominations, cast, crew and producer are finally basking in their achievements.
Earlier last month, they received their laudations in London on Leicester Square's red carpet with the ultimate sanction: a rare co-appearance with the scientist in his trademark wheelchair.
"It was a moral duty to get his blessing, even if it was not a legal one," McCarten says.
He first spoke to Wilde in 2004 to ask for option rights to her book and she took seven years to say yes.
A second trip to meet Hawking was a nerveracking affair as the Cambridge don - severely stricken by his motor-neuron condition - could communicate his approval of the project only through his famous voice machine that produced one sentence every few minutes, via muscle twitches of his cheek.
McCarten points out: "Stephen is not interested in his disease - he is interested in his work and family and he keeps his sense of humour.
"The film honours that."
Of course, there is the physics too. This gets a whistle-stop tour that depicts Hawking's first major breakthrough on reverse-projecting black hole mechanics unto the proverbial moment of the big bang. It also segues into the denouncement of his earlier research in his later career with the publication of A Brief History Of Time in 1988.
While it would have been tempting to present the story as a Hollywoodesque triumph against all odds, McCarten and director Marsh (documentary Man On Wire, 2008) opted for a subtle love triangle.
"There were unusual obstacles, so there had to be unusual solutions," McCarten says, pointing out the arrival of an unlikely likeable third party in a love triangle in the film's second half.