Jennifer Love Hewitt Is Pregnant! Actress Expecting Baby No. 3: Such a 'Beautiful, Surprising Gift'

Jennifer Love Hewitt is about to have a party of five!

The 9-1-1 actress is pregnant, expecting her third baby with husband Brian Hallisay, she reveals exclusively with PEOPLE. Hewitt — who is also mom to son Atticus James, 5½, and daughter Autumn James, 7 — says the news comes as a welcome surprise.

"We had always been open to a third, but definitely didn't think in the crazy year that the entire world was having that it would necessarily be this moment," says Hewitt, 42, adding, "I feel like we've been able to so far raise two really special kids who will be great role models. This has been such a pleasant, beautiful, surprising gift in this time to be able to get to do all that again with another little human."

Hewitt's two kids may be more excited than her about welcoming a new member to the family — so much so that Atticus even guessed that Mom was pregnant before she even knew.

"One night, my kids and I were laying in bed watching TV and a Clearblue commercial came on television. My son out of nowhere was like, 'Hey Mommy, you should order one of those in case there's a baby in your belly,' " she recalls. "I was like, 'How rude! I just ate a big dinner. What is he talking about?' It stuck with me, and they've been asking off and on for a year or so for a sibling. We weren't closed off to the idea, it just wasn't something that we were actively thinking about."

"Sure enough," says Hewitt, the pregnancy test clearly confirmed that she was expecting after she humored her son and took a test.

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Jennifer Love Hewitt/Instagram

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"I was like, 'Wow, this is really interesting that he put it out there in the universe and there it was.' I had used Clear Blue tests before, and it was just really funny that he saw that commercial and said that out loud," says Hewitt, adding that Atticus and Autumn were both "so excited."

Hewitt adds that she's "proud" of herself for keeping her pregnancy a secret until now — even while playing a pregnant woman, Maddie, on screen and simulating an "intense" labor and birth on Fox's 9-1-1, which was recently renewed for another season.

"Because my kids are a little bit older, it was a good reminder of being back in that space again. And [costar Kenneth Choi] was like, 'See? Playing pregnant got you pregnant!' I'm like, 'Yeah, I guess so,' " says Hewitt. "The craziest, most surreal moment was having to give birth while being pregnant. That was very interesting."

"And it was definitely a nauseous day for me. So that came with its own challenges, but it was a good recall back to those beautiful, amazing moments that you feel really excited about," she adds of filming the delivery scene. "I got to remind myself of that and then also be in a really excited place of knowing that I will get to do that again."

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When it comes time to give birth IRL again, the Ghost Whisperer alum says she'll be grateful to have her husband in the delivery room.

"During labor, he's like a rock, solid," she says of Hallisay, whom she wed in November 2013. "You would never know if he was panicked, or worried or stressed or anything — he's just really good. The only thing about him and labor that really makes me laugh is that he eats a lot of snacks. Usually in my hospital bag it is like an outfit for me and outfit for the baby, and then snacks for Brian!"

And while Hewitt says she loves "the experience" of being pregnant, baby No. 3 will likely be her last: "I'm pretty sure. I don't think I could do another one. I think five is a great number."