The movie, an adaptation of the hit video game franchise World of Warcraft, features the battle between humans and orc warriors, who invade Azeroth to escape extinction from their own dying world of Draenor.

To prepare his orc actors for the project, Duncan set up a special training camp so they could all learn how to carry themselves as their movements were captured on film using modern technology, and then transformed onscreen with the help of computer-generated imagery.

During an appearance on U.S. breakfast show Today with actor Rob Kazinsky, Duncan explained, "The orcs have this very specific way that they had to move and walk, so we had a movement coach, who actually took Rob and a bunch of the other people who were doing that work into Orc Camp, where they basically had to learn a vocabulary of movement."

British actor Rob, who portrays brave warrior Orgrim Doomhammer, added, "Our characters are between seven and eight feet tall, five to seven hundred pounds, so they're big guys and you have to move very differently, so we had to find a uniform way of doing that, and then add our nuances to it. It was a month-long, 12-hours-a-day camp; it was really like a real voyage of discovery."

The Pacific Rim star went on to admit landing the Warcraft role was a dream come true as he had previously been hooked on playing the online battle game.

"I was a sponsored player of the game, I played it for 12 years," he revealed. "I used to play for about 18 hours every day, I was dedicated...! So for me making this movie, it's very much kind of full circle, and being in this movie means that spending 10 years of my life, 18 hours a day on something is cool! (It was) research!"

Warcraft, which also stars Travis Fimmel, Paula Patton, Ben Foster, Dominic Cooper, and Toby Kebbell, is due for release next month (Jun16).