(CNN) -- Spring has barely sprung, but Melissa Joan Hart is ready for beach season.
The 37-year-old actress has lost 40 pounds with her gig as a spokeswoman for Nutrisystem, and she's eager to show off what she looks like in a bathing suit.
"It's not everyday I like to show a lot of skin, but these days, I'm feeling confidant (sic)," she wrote on Instagram on April 8 along with a photo of herself in a revealing pink bikini that presumably will be seen in her upcoming commercial for the weight loss company.
On Nutrisystem's website, Hart explains she first signed up for the program because she'd been carrying around an extra 30 pounds after the arrival of her third child, Tucker, who turns 2 in December.
"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."
Hart's been working on weight loss for more than a year, as she first revealed that she'd dropped two sizes in April 2013. But it wasn't until now that she's felt comfortable enough in her skin to wear a bikini.
"It's the first time I've been able to wear a bikini in probably 10 years, that I've felt confident enough to wear a bikini," Hart said on "Good Morning America" on Wednesday.
"I've been able to be fit and healthy, and have enough energy for my (three) boys," she continued, not to mention energy for her husband, Mark Wilkerson. "My husband, he takes care of himself for me, so I need to return the favor, too."
While usually Wilkerson is the only one who gets to see so much of the actress, she doesn't regret sharing her figure with the world. Posting the bikini pic was "scary," she said, "but it was empowering. No hiding now."