The couple, who tied the knot in June, confirmed last week that they will have a baby later this year.
Hilaria has now quipped in an interview with Extra that Baldwin is suffering from sympathy pains, explaining: "His back hurts."
"My boobs hurt," Alec joked. "My boobs are killing me, they're so sore. And my jeans don't fit."
Elsewhere, Alec revealed that his wife has been experiencing cravings, saying: "She was eating troughs of pineapple. We're taking about tanker containers of pineapple."
He added: "My dream is to be home with the baby, standing in the doorway like, 'Mommy's going to work now! Bye, mommy, see you when you come back! Don't work too hard, mommy!' And I'm home."
The couple also revealed that they do not yet know whether they will have a boy or a girl, but Hilaria said: "I want to have at least one of each, so whatever this is going to be, I want to have the next one."
Alec is already father to 17-year-old daughter Ireland from his previous marriage to Kim Basinger.
Watch Alec and Hilaria Baldwin speaking about the pregnancy below: