The announcement was made in Us Weekly's May 22 issue, on newsstands now. Montag, who is 17 weeks along in her pregnancy, received the call not too long ago, "started screaming" after getting the call from her doctor's office. "It was in my heart to have a boy," the former star of MTV's The Hills said. "I thought Spencer really used to want a boy, and then a few months ago we had a conversation where he said, 'Let's just make sure it's healthy. Boy or girl, I don't care.'"
Pratt, 33, is "really excited" to have a mini-me, Montag added. "I hope to have a little girl one day, but for my first child, I really wanted a son. I'm hoping to God that we don't just have one, but if we do, I wanted a son. I thought it'd be a more natural bond for Spencer since he and his dad are so close." The mom-to-be, meanwhile, is "really excited" to see her son's "little smile."
"I'm excited to take him to Disneyland and to see if he's into dinosaurs, Mickey Mouse or ballerinas—it can be anything," the MTV star told Us Weekly. "Maybe he'll be the best dancer!"
Since announcing her pregnancy in April, Montag has heard from Hills co-stars Kristin Cavallari and Audrina Patridge. "I obviously asked both of them for advice," Montag said. "Kristin sent me a whole list of baby things you need in the first few months, which has been really helpful."
Montag also revealed that her baby boy is due in October.
Previously, Pratt told the magazine, "Heidi has wanted to be a mom since the day I met her. She has planned for and thought about this."
His wife added, "The reality is sinking in that we are going to have a child! I've read every pregnancy book, and now I realize I don't know anything."