@mollybsims / Instagram 1 / 13
@mollybsims / Instagram 1 / 13

It's almost unfair that Molly Sims can look this good in a bikini and be pregnant at the same time.

The 41-year-old supermodel, who is expecting her second child with husband Scott Stuber, posted a family photo on her Instagram from the Bahamas. While the bikini-clad mom proudly shows off her baby bump, her fitness is still on point!

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"Family Fun #vacation #muchneededvacation," she captioned the photo of her family amid the crystal clear Caribbean water.

In another image she posted, the supermodel is seen standing on a beautiful beach in a flowing maternity cover-up dress. "Me and baby beaching it! #bakersbay #bahamas @nataliemartincollection," she wrote.

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It will be interesting to see how Molly's second pregnancy will transform her body. While pregnant in 2012 with son Brooks, Molly reportedly gained 72 pounds and she spoke about the difficulty of shedding the baby weight afterward.

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"I would workout for an hour and 45 minutes, an hour and 50 [minutes]," Sims told ABC News. "My neck was … I looked like a football player … I kept asking people, I'm like, 'I don't feel right. Something's wrong with me.'"

It turned out she was correct. Four months after giving birth, Molly was diagnosed with thyroiditis, an inflammation of the thyroid gland. "He was like, 'Uh-oh. Something is wrong with your thyroid," she told ABC News. "My neck was huge. I mean, literally, huge."

After taking medication, Molly's life slowly got back in order. And, as you can see from the picture, she's as beautiful as ever.