Melissa Joan Hart
is one hot mama!

The mother-of-three revealed her 40-pound weight loss on "Entertainment Tonight," who was on set to watch her film a commercial for Nutrisystem.

The blonde beauty credits the weight-loss company for helping her shed the 60 pounds that she gained during her pregnancy with her son Tucker, who was born in September 2012. 

"I love working with Nutrisystem," the actress told ET. "The program is really delivering results for me and I look forward to long-term success, staying motivated and helping others do the same."

"For me, it was important to bond with my child, as opposed to ‘lose the weight.' So I waited until I was ready, and I knew I had the time, and then I made it a priority that I would eat well," the "Melissa & Joey" star said.

"I don't wear bikinis even when I go to the beach, so when I put it on in front of the cameras and all these people, and my husband showed up -- it's nerve-wracking but the feeling is very satisfying," she explained of posing in a one-piece blue swimsuit on the set.

The 37-year-old actress is clearly proud of her post-baby body! She even showed it off in a cheeky pic on Instagram on Wednesday, hiding her swimsuit-clad figure behind a giant sun hat.

"Wanna see what's behind this hat? Check out my new @nutrisystem commercials starting this spring!!" she wrote along with the sassy snapshot.

We can't wait to see the big reveal!

What do you think of her slimmed-down figure? Sound off below, and click "Launch Gallery" above to see more celebrity weight loss success stories.

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