On Saturday, day after she announced she is pregnant with their fourth child, the yoga instructor posted on Instagram a video showing her cutting a cake that revealed blue insides in front of her husband and their three children—daughter Carmen, 4, and sons Rafael, 2, and Leonardo, who turned 1 in September.
"Do you know what this means? This means we're gonna get lots of exercise," Hilaria joked to the kids.
"The magic cake says the baby is a boy," Alec told them. "And we all say together, everybody say, 'Thank you, magic cake!'
After the couple's new son is born, the Baldwin family will officially have four boys—Alec, Rafael, Leonardo and the new child, and three girls—Hilaria, Carmen and Alec's 22-year-old daughter Ireland Baldwin.