The tiny tot strolled through a farmer's market in LA with Garner wearing a blue Batman T-shirt, comfy navy sweatpants and grey-and-green sneakers, reported Us magazine.
Affleck has been roped in to play Batman in the upcoming "Man of Steel" sequel.
Earlier this month, Garner had talked about her husband's new superhero role, saying that she is excited for his project.
"You know, I was excited for him. I was excited because he had a real take on what he wanted to do. I have to say, my husband is a pretty great storyteller himself, and I'm excited to watch him do it," she added.