The Hills are alive with the sound of squealing, as we're giddy about the sight of Kristin Cavallari's growing baby bump!

Kristin and hubby Jay Cutler are expecting baby number two, as they announced their pregnancy in October 2013. They have a 17-month-old son, Camden.

Credit: Instagram

On January 18, 27-year-old Kristin posted an Instagram photo showing off her baby bump. "Gym selfie.... baby bump getting big!" she captions the shot.

Wow! Her bump really is getting big! We can't wait to watch it continue to grow — and we're excited to see what their little one will look like. We also love that Kristin is still managing to squeeze in some gym time, as the Dancing With the Stars alum is certainly diligent about maintaining her amazing physique.

Kristin has revealed that she and Jay already know what the gender of their second child will be, although they haven't made that info public yet. 

Before finding out the gender, Kristin talked about which gender she was hoping for. "Obviously, I want a little girl, but if I had another boy, I would be so excited as well," she said. "I love having a boy. Either way, I’d be really, really happy." Way to be diplomatic, Kristin!

Are you surprised by how big her bump is?

Source: Kristin on Instagram