Carson revealed her pregnancy in July, sharing how the couple couldn't "contain our excitement and joy right now."
Speaking to ET a few days later, she said they were not ready to reveal the baby’s gender, but were both “100%” wrong with their predictions.
During the interview, Carson also admitted she still couldn’t believe that she will be welcoming a child, due to arrive in January.
"It came as a shock because we were not expecting it; we both kind of looked at each other and were very surprised,” Carson said. “So, it's kind of taken some time to digest this news, but ultimately, we are just so excited. And it's just kind of crazy to be growing a human inside me. Like, it's bizarre! I don't even think it's hit him yet at all."
"Yeah, she's still so little. Kind of out of sight, out of mind for me," McAllister then joked. "It hasn't quite hit me yet."
As Carson prepares for motherhood, her DWTS co-star and bestie, Lindsay Arnold, is also navigating pregnancy.
“Lindsay's due in November, and then I'm due in January. Everybody thought that we planned it, but it's so funny because we really didn't," Carson said. "Lindsay told me she was pregnant when she was, like, 11 or 12 weeks. I was already pregnant, I just didn't know it. It was so crazy."