Kutcher revealed the sex of his child in an interview on the Today show when discussing daughter Wyatt's reaction to Kunis' baby bump.
"She points to Mila and she's like, 'baby brother' when she points to the belly and then she points to dad and she goes, 'Beer!' So I think she gets there's something in the belly but I don't quite think that she knows that it's not going to be a plastic doll yet."
But the actor did admit to Seth Meyers that he had secretly hoped to have another girl because he wants a big family.
“First of all — our first girl is unbelievable. But also I figured if we had a girl second, [Mila] might give me one more shot at having a boy and now I don’t know!” he said on Late Night with Seth Meyers in October.
“It’s even money — she might cut me off!”
The That '70s Show co-stars welcomed daughter Wyatt Isabelle in October 2014, and tied the knot in a low-key ceremony in July 2015.