The satirical comedy War Machine, out on Netflix and in select theaters on May 26, is the latest film from Brad Pitt.
The movie tells the story of General Glen McMahon (Pitt), who tries to "win" the war in Afghanistan.
On Tuesday, Pitt answered questions about War Machine during a BuzzFeed News-presented screening and panel discussion.
The actor said he'd previously made a trip to Walter Reed National Military Medical Center in Bethesda, Maryland, and talking with soldiers in the hospital became part of his motivation for getting involved with adapting Hastings' book into a movie.
"The impetus for this film for me was a visit to Walter Reed, and seeing the sacrifice and really looking at it from the point of view as a father," Pitt said.
"I met as noble and heroic of individuals as I've ever met, and I walked away going, 'Why? Why? For what? Why?'"
The actor continued, "It's what made me want to ... and what made us in our discussions, to follow through with a film of this nature."
