Lone Survivor - Clip No. 1
If you're making a movie about Navy SEALs, it makes sense to call on the real deal for some advice. And that's what Marcus Luttrell, author of "Lone Survivor," did when it came time for director Peter Berg to bring his harrowing, real-life story to the big screen.

In the exclusive "Lone Survivor" featurette above, Luttrell explains how he recruited some of the Navy's finest to help make his story more believable in movie form. "I'm still close to the SEAL teams, and there's some pretty important people on the teams that advise me," he says.

"Marcus Luttrell called us up and asked us if we's be willing to train the actors to get them ready for this film," adds military technical advisor Mark Semos, the man in charge of taking the movie's actors -- like Taylor Kitsch and Emile Hirsch, both featured in the clip -- and turning them into lean, mean, weapon-toting machines.

"The main goal of Semos and the SEAL training was to teach these guys how to literally be comfortable with all of this gear, so that when they were filming they looked like they knew what they were doing," adds director Berg, whose dedication to authenticity has resulted in a Screen Actors Guild Award nomination for Outstanding Action Performance by a Stunt Ensemble in a Motion Picture.

Watch the clip above and find out how it's done. If you stick with the clip, you'll even see some pretty intense role play and training simulations.

"Lone Survivor" opens nationwide Friday, January 10.