Kristin's pregnancy won't come as a total surprise to her fans, given how open she has been about her desire to have more children.
In September, the 26-year-old said that she and NFL star Jay hoped it wouldn't be long before they heard the pitter-patter of tiny feet.
"We want to have a second sooner rather than later," she told E!. "We're working on it!
"We know we want another one close in age to Camden, and we're at the point where we're both ready," the former Hills star shared.
"Before Camden was born, I thought I'd be pregnancy again by the time he was six months, but I definitely wasn't ready. Now, I'm finally ready.
"Obviously, I want a little girl," she added. "But if I had another boy I would be so excited as well."
Kristin married Chicago Bears quarterback Jay, 30, in a low-key ceremony in Nashville in June.