Knight, who grew up in Birmingham, said there were “lots of fathers and sons and mothers and daughters” at the stadiums.
“The original generation have grown up and their kids seemed to have found the music for themselves and when they are in the stadium and the music starts playing it was a spontaneous combustion; people were hugging and crying.”
He said he could hear people breaking down about 15 minutes into the film.
“It’s an extraordinary thing that I’ve never known,” said Knight.
“When you write fiction and you write a movie you aspire to having these kind of reactions.
“People are watching real people having real emotions and it is really powerful.”
He said the film about reconciliation had “resonated” with people.
“What we’re finding is people who’ve watched it, they have an emotional reaction to it and afterwards they think, well, you know what, I haven’t spoken to my half-sister for 10 years, maybe I should text, maybe I should call.
“And if that’s the effect it has, then I’m all for it, it’s great.”