Expectations were low when Paul Potts took to the stage in the auditions for the first season of Simon Cowell's TV talent contest, Britain's Got Talent. In line with our cynical, looks-obsessed times, the pudgy and timid Carphone Warehouse salesman was immediately pegged as a loser.
"He was the first of those guys where we're sat at home with our dinners on our laps going, 'Oh, here we go. This will be funny'," comedian James Corden recalls.
However, from the moment Potts opened his mouth and started to sing Nessun Dorma, the aria from Giacomo Puccini's Turandot, all bets were off. Within a few bars, the tenor had stolen the hearts of the nation with his passion and soaring voice, while a YouTube clip of his performance ensured the rest of the world quickly caught up.
The internet footage was all that Corden knew about Britain's Got Talent's first winner when Hollywood producer Harvey Weinstein - who'd seen the London-born actor-writer on Broadway the previous evening in One Man, Two Guvnors - asked him to take on the role of Potts.
Corden admits he was initially dubious about the project. "I said, 'Really? Are you sure? This sounds like a terrible idea'," he recalls. But Weinstein encouraged him to meet the director, David Frankel, who told Corden that One Chance wouldn't be about Potts' 2007 victory, but all that the singer had overcome up to that point.
In this Hollywood-inflected retelling, Potts would be a boy "from a steel town who dreams of becoming an opera singer. That two-minute YouTube clip is moving and powerful and uplifting and positive", Corden recalls Frankel telling him. "Now imagine you have seen everything it took that guy to step on the stage, how much greater that moment would be."
Convinced that what was being proposed was a Rocky Balboa-like underdog story, where opera replaced boxing, Corden signed on.