06/30/2012 10:06 am ET

Pregnant Kristin Cavallari Tweets Baby Bump Photo To Show New Maternity Dress

Kristin Cavallari hasn't been shy about showing off her growing baby bump. Last month, the expectant reality star shared a photo of herself getting ready for a shower in Los Angeles, where guests included former "Hills" co-stars Stephanie Pratt, Heidi Montag and Spencer Pratt.

And Friday, Cavallari, who is expecting a baby boy with her fiance, Chicago Bears quarterback Jay Cutler, took to Twitter to share a photo featuring a new green frock from maternity shop A Pea in the Pod.

Cavallari has been positively glowing, and Montag recently told Us Weekly, "She is the most beautiful pregnant woman I've ever seen and I'm very proud of her."

Cavallari, 25, announced that she was pregnant in January. In May, the baby's sex was revealed to the public by Cutler's teammate, Chicago Bears wide receiver Earl Bennett, during an appearance on "The Boers & Bernstein Show" on WSCR-AM 670.

Earlier this year, Cavallari told Glamaholic that she and Cutler were surprised when they learned they were going to be parents, but they couldn't be happier.

"Your motherly instincts naturally kick in," Cavallari said. "We weren't trying to have a kid but we weren't not trying, we left it up to fate. I knew there was a possibility but I was really excited! Even if you are trying, just to see a positive result is shocking!"

See more stars who are expecting in 2012:

Celebrity Babies On The Way