Behold: Lingerie-Clad Hilaria Baldwin Works Out in Bed

So that's how she got those arms. 

Hilaria Baldwin is one fit mama—and lucky for us, she's not afraid to share glimpses of her workout regimen with her followers. The yogi—who is married to Alec Baldwin and expecting her third child—shared one of her go-to prenatal exercise moves while perched on a coffee table a few weeks ago. Now, she's giving us all a peak at yet another prenatal workout she employs...and because this is Hilaria Baldwin we're talking about, she does it while sitting in bed.

Hilaria is also wearing just a bra and pair of undies in the video, and her body and baby bump are gorgeous. This particular video gives us an idea of how Hilaria likes to work her triceps: She's using a seven-pound weight and performing three sets of 15 reps. 

The model has always been super dedicated to maintaining her fit lifestyle, and she's equally committed to sharing her tips so that others may live their healthiest lives as well. Though she's known for her yoga expertise, Hilaria loves to mix it up when it comes to her workouts. "I'm a runner. I teach myself yoga every day, and I'm hoping to start swimming, which is supposed to be incredible when you're pregnant. You feel weightless, or so I've heard," she told Fit Pregnancy.

Our Fit Pregnancy and Baby cover girl opened up about the importance of staying active through pregnancy as well: “So many women give up. They think, I’m a mom now, so I’m always going to be out of shape. No! I’m of the opinion that just because we’re pregnant doesn’t mean we’re sick. Let’s be strong and in the best shape possible. I still jog four miles, four days a week, though I plan to switch to swimming soon. I do barre class three times a week. And I do yoga every day. For me, it’s all part of having a healthy mind-set," she said.

Will you give Hilaria's simple tricep-toning workout a try? Will you be doing it in beautiful lingerie like Hilaria does? Tell us!