All Hands on Deck! ET's 'Battleship' Exclusive

This is huge. ET's Mark Steines is exclusively on deck with the cast and crew of Battleship on the USS Missouri in Pearl Harbor, HI. We break down the action…

Actor/director Peter Berg (Friday Night Lights, Hancock) is the man calling the shots behind this mega-production that's employing 3000 extras (including real Navy sailors integrated among the costumed atmosphere) over the 70-day shoot in Oahu and Baton Rouge.

"It's the biggest thing I've ever done. … On a day like today we have 800 extras, we have a very large cast, we have a massive crew, it's a full-on zoo," says Berg. "There's no easy days on this film. Every day is an exercise in problem-solving and logistics, but it's fun and I like it. … We quote John Paul Jones, the founder of the American Navy, and generally say, 'We're going into harm's way.'"

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The USS Missouri, nicknamed "The Mighty Mo," fought at both Iwo Jima and Okinawa during WWII. The largest battleship ever built by the U.S., the vessel is the length of three football fields, weighs 45,000 tons, and has the distinction of being the last battleship ever built by the U.S. Navy.

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Based on Hasbro's classic naval combat game, the epic action-adventure unfolds across the seas, in the skies and over land as our planet fights for survival against an out-of-this-world, superior force.

"We are, on Earth, currently sending out beacon signals into outer space in the hopes that somebody hears them and comes and visits us," says Berg. "And as Stephen Hawking says, that's probably not such a good idea."

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Manning Battleship is Taylor Kitsch as Hopper, a Naval officer assigned to the USS John Paul Jones; Brooklyn Decker as Sam, a physical therapist and Hopper's fiancée; Alexander Skarsgård as Hopper's older brother, Commanding Officer Stone of the USS Samson; Rihanna as Lt. Raikes, Hopper's crewmate and a weapons specialist on the USS John Paul Jones; and Liam Neeson as Hopper and Stone's superior (and Sam's father), Admiral Shane. Japanese star Tadanobu Asano also appears as Capt. Nagata, Commanding Officer of the Japanese Destroyer Myoko -- and Hopper's archrival.

Battleship explodes into theaters summer 2012.