After losing 40 pounds, Melissa Joan Hart is showing off her new, slimmer figure in a sexy new ad that she posted on Instagram.

The 37-year-old actress says that she gained 60 pounds while carrying her third child, Tucker, in 2012. However, she's says that Nutrisystem helped her shed the extra pounds and now the "Melissa & Joey" star is showing off her toned down figure in bikini pics that she posted on Instagram. She captioned the revealing photos with "It's not everyday I like to show a lot of skin, but these days, I'm feeling confidant [sic]."

As the spokeswoman for Nutrisystem, she explained why she signed up for the weight loss program on Nutrisystem's website, saying, "Simple things like bending down to pick up toys or walking up the stairs were difficult," she says. "I just wasn't able to keep up with my active boys. ... Everyone thinks that when you live in Hollywood, you have an entourage of people doing everything for you. The truth of the matter is, I'm a working mother of three. I don't always have time to go to the gym; I don't always have a trainer available to me. So it's important for me to eat right."

Back in December, the mother of three confessed, "I was so sick of things not fitting properly," to Us Weekly.

Since going on Nutrisystem last February, the former "Sabrina the Teenage Witch" star told Us Weekly that she has "lost three jean sizes, and all my baby weight and then some." Instead of setting a specific goal, she says, "I just wanted to put something on and be like, 'okay, good,'" she confessed. "I have been able to forgo the Spanx...and its been really nice."

She also revealed that she took her time working off the weight.

"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," she said.