@kristincavallari / Instagram 1 / 7
@kristincavallari / Instagram 1 / 7

Us Weekly

Are her party days dunzo? Former "Hills" wild child Kristin Cavallari seems to have permanently traded late nights at Les Deux for tame celebrations. The pregnant mom of 16-month-old Camden celebrated her 27th birthday on Jan. 5 with her husband, Jay Cutler, and posted a picture of the laid-back evening on Instagram.

PHOTOS: Kristin's chic pregnancy style

"Thank u for all the birthday love. Enjoying a 'mock-tail' for the big 2-7!" she captioned the picture.

The couple announced in October that they were pregnant with their second child and told Us Weekly in December that they had asked a doctor to write the baby's gender on a note and put it in an envelope.

"We're going to open it on Christmas -- Jay and I," she revealed.

PHOTOS: Kristin's life as a mom with Jay Cutler

But, post-Christmas, the couple has yet to announce the sex of their future bundle of joy. In September 2013, Cavallari told Us Weekly, "I would love to have a little girl, but if I had another boy, that would be great too."

Cavallari became a household name after starring in two seasons of "Laguna Beach" before transitioning onto "The Hills" in season 5 to replace Lauren Conrad in the lead role.

PHOTOS: 'The Hills' stars, then and now

Fessing up about her MTV days, the outspoken star recently told Bethenny Frankel on her talk show, "I faked relationships, faked fights. I don't care anymore -- I can tell you. At this point, it's been so many years."