Peter Berg takes command of 'Battleship' action

Berg also enlisted an active-duty soldier — Greg Gadson, who directs the Army's Wounded Warrior Program — in another key role after seeing the massive colonel's striking photo in a magazine. The role required Gadson, who lost both his legs to an improvised explosive device in Iraq in 2007 — to climb a mountain in Hawaii and grapple in a fight sequence while wearing his titanium prosthetics.

"Pete is very on-the-fly," said Gadson. "We would start rolling. He would say, 'How would you do it? How would you say it?' He was very flexible and very willing to listen. I told him, 'You're really kind of like a coach.' He would talk to us in different ways, to motivate and inspire and communicate. You kind of just want to be around him."

The film's production took place in Hawaii, at a military rehab facility in San Antonio and on soundstages in Louisiana throughout much of 2010. While filming in Pearl Harbor, where 2,400 Americans were killed by Japanese fighters 71 years ago, another ship had caught Berg's eye.

"There was a Japanese warship tied up next to an American warship," Berg said. "I was just sitting there staring in shock at the Japanese flag and the American flag side by side. I didn't realize the extent of the cooperation between our militaries. My grandfather would roll in his grave if he could see it."

The awareness that two former enemies had become so close militarily inspired Berg to add the character played by Asano — the Johnny Depp of Japan — who steps into a leadership role during the alien attack. The casting has helped the film find its audience internationally: "Battleship," which had its world premiere in Tokyo last month, has grossed more than $170 million abroad.