20 Things You Didn't Know About Gone Girl

David Fincher stated that he cast Ben Affleck in the part for one particular reason while he was still fielding candidates.

When casting actors in his movies, the director generally goes online and sifts through pictures of actors to get a feel for how they look in various situations.

When Fincher googled Affleck, he noticed that the actor had the same, specific smile in dozens of the pictures, which he felt made him perfect for the pivotal scene where Nick smiles at the press conference. Fincher said:

"You cast movies based on critical scenes. In Gone Girl there's a smile the guy has to give when the local press asks him to stand next to a poster of his missing wife. I flipped through Google Images and found about 50 shots of Affleck giving that kind of smile in public situations. You look at them and know he’s trying to make people comfortable in the moment, but by doing that he's making himself vulnerable to people having other perceptions about him."