"We are so excited," Haibon said. "... It was weird because we found out the gender in an email. [It was] so 2021."
Now that they know the sex, Haibon said, "It is so much more real to me now because instead of saying 'my kid,' I say, 'my son.'"
As for their hopes for their son, Haibon said he's crossing his fingers that the tot "likes some of the things I liked growing up."
"I've always dreamed of coaching my son's little league team, so hopefully he likes baseball," he added, before Iaconetti revealed her wishes, after initially hoping for a daughter.
"I did want a girl... I always wanted to do the boy band thing and the princess thing," she explained, before quipping of her son, "He'll have to be in a boy band."
The couple was right about their baby's sex, as they told ET's Katie Krause last month that they both had a "gut feeling" that they had a boy on the way.
"He thought it was a boy before we got pregnant. He's been saying, 'Our first is going to be a boy,'" Iaconetti, 33, said of her husband. "I just had a gut feeling about that too. I think it's just because I want a girl so bad that I know it'll probably end up being a boy."
While Iaconetti was hoping for a girl, Haibon, 32, said he was "indifferent" about the baby's sex as he hoped to have both a girl and a boy eventually. Still, he told ET that finding out the sex was "definitely" the part of Iaconetti's pregnancy he was most looking forward to.
"That's when I feel it's going to start feeling very real because we're no longer referring to the baby as this thing," he explained.
Whether it had been a boy or a girl, the longtime Patriots fan joked, "I'm going to get [the baby] a Tom Brady jersey early on."
With a boy on the way, the couple is prepared, as they've long had their son's name picked out.
"I've had this name [picked out] since I was, like, 20 and Jared really liked it," Iaconetti told ET of the boy's name she's long loved.
"The name that she picked out, I love for a boy," Haibon agreed. "We actually just figured out the middle name as well. If it is a boy, we have the first and middle name all set. We love movies, and there's a little nod to a couple of films in the name, which is ridiculous, but also so meaningful to us. It's a great name and we love it. Nobody would know, except for us."