You have director David Fincher to thank for this scene as he insisted on having Affleck in the nude. "It's ironic, because David said to me from the beginning, this is a warts and all movie. It can have no vanity. You have to see the naked underbelly of this character," Affleck added. Turns out, he meant "naked underbelly" literally.
So what exactly can we expect from this full-frontal display? "There’s some brief, ah, very brief nudity, I think," the actor said sheepishly before continuing, "The penis is in there! It’s IMAX penis! You’ve gotta pay 15 bucks to see it in 3D… it’s better in 3D."