"I'd never made a sports film before, and I really wanted to try that out," said Waititi. "It's about a sport I don't know that much about.
"Rugby is the national sport in New Zealand, but it's about underdogs, and I just love underdog stories.
"Most of my films are about people who live on the margins, or are a little bit left out, and it just fit right in for me.
"It's a true story, but it's got all the elements that all the great sports films have. It's basically the 'Cool Runnings' of soccer."