Garner's response to her husband baring it all, "'You're welcome.'"
She added jokingly, "I just try to consider myself a charitable person and I wanted to give back. You give me so much, I wanted to give something back to all of you."
As for how Affleck, 42, brought up the scene to his wife, Garner admits that the conversation was casual. "It wasn't a discussion, it was like, 'Hey, at work today [director David] Fincher talked me into coming out of the shower,'" she recalls. "And I was like, 'Oh, cool, well, I hope he had on a wide lens.'"