Jessie James Decker and her husband Eric Decker have learned the sex of their baby-to-be, but they're not sure whether or not they'll do a public gender reveal before the baby is born.

"I haven't decided if I'm gonna share or not," Decker says in a new interview with ET. But she adds that she has told her three children — nine-year-old Vivianne Rose, eight-year-old Eric "Bubby" Jr. and five-year-old Forrest Bradley — and they haven't been quite as tight-lipped about keeping the secret.

"If you were to go to their school right now and ask somebody, you would know the baby, and you would know the baby's name," the singer jokes. "They do not hold back."

Decker's fourth child is due in early 2024, and she admits it "took a while for the surprise to wear off" after she got pregnant. As of last year, the couple were adopting a "what will be, will be" approach to family planning, and the singer explained at the time that she was on the fence about whether or not to have another baby.

Still, she explains to ET, the couple weren't consciously planning another baby. When she told her husband she was pregnant, he was so surprised that he thought she was pranking him.

"So my sister was still pregnant at the time, and he thought that she had peed on the stick and we were playing a joke on him," Decker recounts. "So he made me pee on the stick in front of him. He didn't believe me."

Though the news was unexpected, Decker says she and Eric are "over the moon," and that both members of the couple have long had a suspicion that their family might not be quite complete yet. She's previously talked about the fact that her husband has had vasectomy appointments booked, but for whatever reason, they never wound up taking that final step.

"Throughout these years, when we're with the kids and we're all, like, holding hands, we're walking somewhere, I'd always be like, 'We're missing one,'" Decker continues. "And I'm like, 'Oh my God, no we're not. We don't have four children. Why do I keep thinking that?'"

With baby No. 4 now on the horizon, though, Decker says she's confident that they won't be expanding their family any further.

"Yes, oh my God. We are not going for a fifth. For sure," she adds with a laugh.

As she prepares to welcome a new baby into the family, Decker is working hard on the next career chapter, too. Decker's latest single, "I'm Gonna Love You," is out now, and she's also at work on a holiday project that will feature some guest appearances from her kids.

"Maybe you're gonna see some little talented Decker children making a feature on it," the singer hints.

PICTURES: See Inside Jessie James Decker + Eric Decker's Lavish Nashville Mansion

Jessie James Decker and her husband, Eric Decker, are selling their stunning Nashville mansion, and pictures show a lavish property with every upscale amenity one could want.

More From 102.7 KORD