"Sometimes I find it's harder to workout on vacation than when home because the kids have no classes etc...so I wait until nap time!" she captioned the mirror selfie, which was taken during her family's Florida getaway. "It was a hot run down here in Florida -- but enjoying one more day until we head home to NYC."
"Took this #BaldwinBabyBump3 for a hot jog...so good!" her post continued. "Taking it slow and staying hydrated in the heat. #366daysoflivingclearly #HilariaLCM."
In March, Hilaria's husband, Alec Baldwin, announced the exciting news on Instagram that the two were expecting their third child together.
"Ireland, Carmen, Rafael, Hilaria and I are excited to share with you that we are going to have another little addition to our family," the 58-year-old Concussion actor captioned the sweet photo of the pair mid-lip lock and holding a teddy bear. "Another little boy coming this Fall."
The two are already parents to 2-year-old Carmen, and nine-month-old Rafael, who dipped his toes in a pool for the very first time during the low-key vacation.
This isn't the first time Hilaria has showed off her growing belly. She's been very vocal about the importance of celebrating "amazing" pregnancy bodies as of late. Last month, Hilaria snapped a pic of herself flaunting her third baby bump in lacy lingerie.
"I posted belly photos every two weeks when I was pregnant with Rafa. I didn't have the guts to do it the first time around with Carmen," she explained. "The purpose? To show that we don't need to be ashamed or hide the pregnant figure. These are common emotions in our society that elevates a thin body above all else."
To hear more on her sexy pregnancy selfies, watch the video below.