Sean and Catherine are already parents to sons Samuel, 3, and Isaiah, 1.
In an interview with ET earlier this month, Sean, 36, revealed that he and Catherine, 33, were waiting for the birth to find out if they were having a boy or girl.
"We're going to be surprised, just like we were with our first two," he said. "We've got a list of names. We're not sharing them, but we've narrowed them down. We got a couple boy names and a couple girl names, and hopefully, by the time it comes, we will pick the one."
Catherine, meanwhile, revealed they hadn't been able to prepare much for being a family of five, given the busyness of the holidays. "We haven't prepared much, because of all the chaos and Christmas coming up and our businesses," she confessed.
"We're trying to sleep train Samuel so he's not injuring the baby when it sleeps in our room because at three years old, Samuel's definitely feeling more confident about doing whatever he wants at whatever time he wants," she shared. "So, we're trying to just set boundaries and expectations for our family."
"I've definitely been preparing to be super present with my kids now because it's going to be a very different chapter in a couple weeks," she added.
Sean and Catherine married in 2014, just over a year after his season of The Bachelor.