'The Hills' alum Whitney Port expecting first child

Feb. 10 (UPI) -- Whitney Port is going to be a first-time mom.

The 31-year-old television personality announced Thursday on Instagram that she's pregnant and expecting her first child with husband Tim Rosenman.

"Oh hey! Just standing by the window in my underwear, with a BABY in my belly!!! 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," she joked. "We are sooooo excited!!!!"

The Hills alum followed up with a blog post and a series of photos on her website. She said she and Roseman were "a bit shocked" by the news, but said she "can't wait" to become a mom.

"I peed on a stick and now I'm going to be a mom! Timmy and I were a bit shocked, but so excited to begin this journey," the star wrote.

"It's been such an interesting and trying but amazing journey already. I can't wait to share my experience AND learn so much from all of you! I can't wait to be a mom, but the fact that there is another person inside there is seriously crazy!" she said.

Port's announcement follows word that her former Hills co-star Lauren Conrad is also pregnant. The television personality and designer, also 31, is expecting her first child with husband William Tell.

"Happy New Year! I have a feeling 2017 is going to be the best year yet..." she captioned a photo of her sonogram in January.

Port and Rosenman married in 2015 after three years of dating. The reality star is known for the MTV series The Hills and The City, and has since appeared on America's Next Top Model and Britain & Ireland's Next Top Model.