Whitney Port is known for her infamous facial expressions during her Hills and City adventures -- and it's time to break out the excited visage because the MTV vet is pregnant!

The fashion designer -- who married Tim Rosenman in November 2015 -- is expecting her first child, she happily shared on Instagram. Hello, bare bump!

"Oh hey! Just standing by the window in my underwear, with a BABY in my belly!!!" the mama-to-be captioned the snapshot above. "DM me if you know what I'm supposed to do with this thing for how ever many years I'm supposed to be in charge. Check out my blog for a little letter from me & Timmy and for more behind the scenes of this crazy journey!!!! We are sooooo excited!!!!"

And speaking of her website, the 31-year-old elaborated about this milestone event there, and her enthusiasm is palpable.

"When two people love each other so much and the love becomes too great to fit inside both people, it spills over into a THIRD person," she wrote. "This is how I am going to explain where babies come from to the little baby that is now growing inside my belly because Timmy and I are PREGNANT!"

Whit continued that she "can't wait" to share this experience and couldn't help but marvel, "The fact that there is another person inside there is seriously crazy!" While the SoCal native didn't divulge the gender, we're willing to bet the names Tiff and Criss are not in the running if she's having a girl. And even though there's no word on the due date, this bun in the oven will be very close in age to Lauren Conrad's peanut!

Share your congratulatory messages for Whitney and Tim in the comments, and stay with MTV News for baby updates!