When the All Blacks won the Rugby World Cup last year, very few people knew the most intimate moments of the team build-up were being captured on video.
Filmmaker Michelle Walshe was granted extraordinary access to captain Richie McCaw and now we too get to see it.
Forty-eight hours before the All Blacks' make or break quarter final re-match with France, Walshe was the only media allowed near McCaw.
"There were a number of times when I just stopped for a moment and just pinched myself and thought, 'What an extraordinary privilege," she says.
But McCaw was a reluctant participant.
"His first response was, 'Why would anyone want to watch 90 minutes about me?', which is hilarious," Walshe says.
"He just didn't think there was a story there."
Chasing Great opens next week and he still needs convincing he's a worthy subject.
"I'm still struggling to believe that my story has ended up in the cinemas," McCaw says.
"It's a little bit scary to be perfectly honest."
The documentary follows McCaw through the last 365 days of his career, a year packed full of tension - could he lead the All Blacks to do what no other team had done?
"It was outrageously nerve-racking," Walshe says.
McCaw says he's pretty happy with the ending it has.
"In sport there's no guarantees and that's why we keep turning up," he says.
We all know how the story ends, but the filmmakers say it's what you learn about McCaw along the way that makes this movie.
"It's a character study of someone who is incredibly driven in the same way you could have Sir Edmund Hillary or Peter Snell, people who excel to that level - Lydia Ko, or you know even maybe Lorde," co-director Justin Pemberton says.
And it seems the reluctant subject has finally come around.
"I sit here now pretty proud of what everyone's done to put it together," McCaw says.