Some of the most heartfelt moments in the against-all-odds biopic about British tenor Paul Potts' path to fame barely required any acting from the cast onscreen.
The emotions on display at the climax of One Chance were as genuine as when the actors first saw the real-life public audition for TV's Britain's Got Talent that sparked Potts' journey to stardom.
"When we shot that scene in the film...we did it all day and there was not one take that I was not moved by," said Welsh actress Alexandra Roach, who plays Potts' wife in the movie, which had its world premiere at the Toronto International Film Festival.
"You remember where you were when you first watched his first audition. There was hardly any acting required in that scene because he does all the work for you."
Potts won over audiences world-wide in 2007 after he auditioned for the televised singing competition, triggering the start of an opera career that has since seen him make his own album and even perform for the Queen.
One Chance goes back to Potts' life before he became a media sensation, tracking the tough road he and his wife travelled to the top.
Making the film had an element of surrealism for Roach, who remembers exactly when she first heard the real Potts perform on live television.
"I was in hospital at the time, and I had three older women with me and we watched on our little TV in our ward Paul singing," she recounts.
"I remember him coming on and just being utterly blown away by him. When he walked onstage everyone didn't expect that much of him and then he opened his mouth and this incredible singing voice appeared and it moved all of us."
To have gone from being a fan to starring along James Corden, who plays Potts in the film, has been quite the experience, said Roach.
"It's been a mad journey to think that I was in hospital watching him on television and now I'm here playing his wife," she said with a laugh.
Italian actress Valeria Bilello, who plays a classmate when Potts goes to Venice for opera lessons, said she felt a connection with the singer's story before the film was made as well.
"I remember really well when I watched the audition for the first time, and I feel the same way every time I watch it, it's really, really moving," she said.
That connection with an ordinary person's story was what drew director David Frankel – the man behind films like Marley and Me and The Devil Wears Prada – to make the film.
"I had seen the YouTube clip (of Potts' audition), 90 seconds later I'm weeping and I felt that's incredible," he said.
"It turned out that the story leading up to those few minutes was as compelling as the ending. The how and the why of it all and especially this romance ... It just stayed with me."
One Chance hits theatres in the U.K. in late October. The Toronto International Film Festival runs through Sunday.