The real -- action heroes that took out Osama bin Laden and a lot of what the Navy SEALs -- seems like it's out of a movie. Well now there is a movie of actual sales in real training for future... See More
The real -- action heroes that took out Osama bin Laden and a lot of what the Navy SEALs -- seems like it's out of a movie. Well now there is a movie of actual sales in real training for future missions. And you just couldn't make some of this here's ABC's Martha -- What you're watching here I got on -- seemingly tranquil scene. Some Covert surveillance. -- of -- assault on the boat by bending him. Actions that could be ripped from recent headline. But it's a Hollywood movie. -- -- -- Those men in uniform. I was real Navy SEALs. Lieutenant commander -- Denver has been a feel for thirteen years very strange to go from real world missions -- the consequences are. As high as there can be in anything in the world to one where you get to walk away from his real life experiences with his fellow seals. Gives the rest of us a firsthand look it just how these commandos operate. Any time we go to film -- -- there'd be. Pre existing training opportunity. That we're doing with regular navy aircraft surface vessel -- service vessels and so -- Seals get their name from sea air land and we see them it would -- From -- high altitude parachute jumps. This silent and deadly assault from the seat depicted in the movie. They take no prisoners attacked -- The movie act of valor is -- Fictional story that is close to the truth that you couldn't -- These high impact scenes are all based on real life mission. These men. Are such a complex of complexity of character that to be really hard for an actor authentically. Portray them and we better deceive you -- -- the real guys to do it. Or two years filmmakers shock wore off and mouse McCoy worked around sealed the deployments in order to get the real guys in the movie. So you're gonna see some things in this film here -- saying no way that I went through that but it actually happen. So we didn't create any fantasy elements there. And that was the deal breaker that sealed if they were going to star in a Hollywood movie they wanted control of proceedings they thought had gone to Hollywood. In a mission that's a lot more calm and collected and disciplined so. -- the value gonna see during a gun fight very calm and tempered communication and that that's the way it really happens. You'd be looking at the scene and they've -- row I would never do that I would do it like -- -- -- That's even better than anything we thought -- For an extra shot of danger and adrenaline the -- -- wanted and got. Live ammunition. Not -- Lieutenant commander brought Denver and his fellow seals didn't need a lot of coaching. There are lots -- didn't need to reversing things we've done a thousand times we've called -- aircraft fire was called in boats to help was on fire -- And talk to one another on missions when bullets or fly so it wasn't new for us in that Barton and that made a lot of phone. Fun -- has a different definition for the seals them for mere mortals seals say they're having fun. Running for miles in wet sand carrying logs into the ocean and back. Being sleep deprived for days all part of the rigorous training that -- Here's that for those jaw dropping missions there were 21 originals who were a laugh from that 200 and. Eric brightens loved being a C. He's written a book about -- -- experience and still relishes the waiting the agony he went through. One of the toughest pieces underwater is an exercise called -- He jump in the pool and in the defeat tied together and hands tied behind your back and have to swim fifty meters. What's the secret to success there this secret to success is com. Everyone's afraid as you go through seal -- -- -- freight in the drown proofing your freedom fifty meter underwater swim. You're afraid when you have to land small rubber boats on jagged rocks in the middle of the night. But the key is to be able to control your fear and focus just on what you have to do in order to be successful in that some worry the movie may reveal too many secrets of the community where -- -- it's absolutely critical that certain things remained secret. That's essential to the safety of the seals themselves and it's essential to our ability to continue to conduct operations in the future. So while the movie thumbs -- for a glimpse into the lives of these dedicated for years. We just have to imagine how -- next realized rate will go down. For Nightline I'm Martha Raddatz in Washington.
This transcript has been automatically generated and may not be 100% accurate.