In the sweet photo, which was also posted to Instagram, the 30-year-old fashionista rocked a nude cardigan over a striped maxi dress. Conrad looked glowing as she held her blond locks away from her face, flashing a smile while looking down at her belly.
"Oh hello, cutest baby bump ever!" a caption from Team LC read. "@laurenconrad, we can't wait to meet your little bundle! ? more on laurenconrad.com."
"Happy New Year!" she wrote alongside a photo of her sonogram. "I have a feeling 2017 is going to be the best year yet..."
On Sunday, ET caught up with Conrad's Hills co-star, Kristin Cavallari, at NBCUniversal's Golden Globes after-party, where she couldn't stop gushing over the exciting news.
"I haven't talked to [Lauren] in years, but what an exciting time in her life!" she exclaimed. "I'm so happy for her, and it's cool to see the evolution of everybody from The Hills and Laguna Beach and to see how everyone is growing up. It's been really fun to watch!"