Molly Sims is currently four months pregnant with her first child, and the 5-foot-9 supermodel is making changes to her wardrobe that she has never had to before.

At the Safe House premiere in NYC Tuesday, the glowing mommy-to-be hit the red carpet in a BCBG number teamed with Lorraine Schwartz jewelry chosen by star stylist Rachel Zoe, plus heavy-duty  undergarments to smooth out her baby bump!

"I'm wearing Spanx! They're holding everything in!" Sims, 38, exclaimed to Us Weekly about the fan-favorite shapewear brand. "I have seen fat deposit in places that I have never seen! I broke down and went to A Pea in the Pod the other day -- I had to buy a new bra!"

The Project Accessory host announced that she and her hubby Scott Stuber, who wed in September, were expecting early this summer. And even though her body is adjusting to carrying a baby, she's still sticking to her usual healthy ways.

"I'm still doing Tracy Anderson, just not at the same high level that I was," she tells Us about her exercise regimen with the celeb trainer. "I've definitely taken it down, because you have to keep your heart rate between 140 and 150 so, it's hard, I'm not gonna lie."