Pregnant Gretchen Rossi Poses in Bra and Undies

“Real Housewives of Orange County” alum Gretchen Rossi is showing off her tiny baby bump!

The 40-year-old took to Instagram to pose in Calvin Klein bra and panties, telling fans her baby is currently the size of a nectarine!

Rossi took the pic two weeks ago, when she was 16 weeks pregnant.

“I didn't get a chance to post this pic from a of couple weeks ago, but here is a pic of my little baby bump! As you can see I don't have much of a bump yet, but when I take it from different angles it shows a little more (like in pic #3).”

She continued, “I am #18 weeks today so need to take another pic because my belly has definitely grown some!”

Gretchen is feeling better now that she's in her second trimester, saying “weeks 14-17 have been a lot better for me, thank goodness!”

The star added, “This whole growing a baby inside of me has been the most amazing thing I have ever experienced! My body is changing and definitely expanding but I am taking it all in stride and enjoying every minute of it! Just so very grateful for our little one on the way! Doing a Gender Reveal Party here very soon! So stay tuned!”