Former reality star Audrina Patridge is expecting her first child with her professional BMX star fiancé Corey Bohan, reported E! News. Patridge, who is best known for her role on the popular MTV reality series "The Hills," announced her pregnancy in an Instagram post today.

The 30-year-old TV personality uploaded a photo of herself, surrounded by Christmas presents and wearing a black top with a black-and-white polka-dot scarf. In the shot, she held up her positive pregnancy test to the camera and smiled.

"I finally figured out what to get Corey for Christmas! #babyontheway #ClearblueConfirmed #ad (blog post with all the details will be up today, couldn't wait to share the news with you all:)! Xoxo," she wrote in the caption.

Patridge, who just announced her engagement to Bohan, 33, in November, opened up to Us Weekly about her reaction to her very first pregnancy and said she was so excited, she couldn't believe the test was real.

"I asked him to have a look at the test and make sure I wasn't seeing things!" she told Us Weekly. "You never really expect it to say 'Pregnant.' He had a big smirk on his face and was really happy about it."

The couple has dated on-and-off since 2008, according to E! News, and Bohan even made several cameos on "The Hills." While the pregnancy news came as a surprise, the couple is looking forward to becoming parents. Patridge said that she will even document her journey to motherhood on her blog, The Inside Out.

"I feel at this point in my life I am ready to be a mama!" she said.

See Patridge's pregnancy announcement below.