Filmmaker Peter Berg became the first civilian to join an active Navy Seal unit while he was preparing to shoot the film adaptation of Marcus Luttrell's book Lone Survivor. Luttrell gave Berg the rights after turning down several directors and then went out of his way to make sure the moviemaker knew exactly what it meant to be a Seal. He tells WENN, "For me research was everything. The Navy Seals are not shy and if you get it wrong they will not hesitate to tell you, particularly when you're portraying their brothers who are dead. "It took a long time to make this film because I needed to have as good an understanding of what their world was before I felt confident enough to go on the set. When Marcus told me he was gonna let me do his film, it was a great honour. He made it very clear that I would understand who he was and who these men were. "Marcus arranged for me to meet all the families of the soldiers who were killed. He arranged for me to spend a lot of time with the Navy Seal community. I got to go to some pretty classified facilities where Seals were training. He arranged for me to get an embed with a Seal platoon in Iraq. I was the first civilian to ever embed with an active Seal team. "The next thing I know I'm in a military plane with three Marines sleeping on top of me, flying for 18 hours, with an outhouse on board as the bathroom! Thank you Marcus for that plane ticket."