The 49-year-old actor revealed that he decided to be part of the 'zombie' project for his children, reported Ace Showbiz.
"Listen, five years ago, I knew absolutely nothing about a zombie. Today, I consider myself an expert. This whole thing started because I just wanted to do a film that my boys could see before they turned 18, one that they would like, anyways. And they love a zombie," said Pitt.
The Golden Globe Award-winning actor said that he and the crew had to face some challenges before starting the production.
"World War Z" is directed by Marc Foster and penned by Matthew Michael Carnahan and J Michael Straczynski. The hits the theaters on June, 21.