Pregnant Jennifer Love Hewitt Debuts Her Baby Bump in a Bikini: 'Hot Bump Summer'

JENNIFER LOVE HEWITT / INSTAGRAM

Jennifer Love Hewitt is bumping along!

On Friday, the 9-1-1 actress, 42, debuted her baby bump in a selfie posted to her Instagram Story, just three days after announcing exclusively with PEOPLE that she is expecting her third child with her husband Brian Hallisay.

Hewitt, who is also mom to son Atticus James, 5½, and daughter Autumn James, 7, shared a picture of herself lounging poolside in an orange and white checkered bikini, showing off her growing belly.

"I am officially declaring hot bump summer!" the star captioned the photo.

When announcing her pregnancy earlier this week, Hewitt told PEOPLE that the pregnancy news came as a welcome surprise.

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"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," said Hewitt, 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 son 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 recalled. "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."

After she humored her son and took a pregnancy test, Hewitt said that "sure enough" the test clearly confirmed that she was expecting.

Steve Granitz/WireImage Jennifer Love Hewitt

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Hewitt said Atticus and Autumn are "so excited" and they've been asking for a sibling "off and on for a year or so." They've already started mapping out what role they want to play in caring for the baby on the way when they arrive.

"They're really looking forward to it," she said. "They've both done some practicing what jobs they'll have — but, definitely, they both have fully decided there will be no diaper-changing for them, which I respect and wouldn't expect them to do, honestly!"

"That was clear from the word go," Hewitt added of her kids' ground rules in regards to diaper duty, "they were like, 'Yeah, this is great, but we are not changing it.' That's fine!"

"I feel like we've been able to so far raise two really special kids who will be great role models," she added. "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."

As for what Hewitt intends to name baby No. 3, she said it's still up in the air — and she's feeling the pressure. "For me, even more so than labor, naming a child is literally the hardest part of it all. It's who they become. It's their person. It's very daunting. We have thrown some [names] out there and there's some thoughts on it, but nothing is solidified yet," she said.