Backstreet Boys singer Nick Carter and his wife, Lauren Kitt, are opening up about the arrival of their third child -- a surprise they never expected.

"It was a shock," said Lauren in an interview with "Good Morning America."

The 37-year-old said the pregnancy was a surprise since she experienced multiple miscarriages in the past and thought she couldn't have another baby.

"I didn't think it was possible to have another child. It was a 1% chance, 1 in 500 at my age," she said. "It was even less than that for my medical conditions, my medical history. And so I was just living my life with my two children and going on as if, you know, I was never going to have anymore."

Lauren, who explained that she was on a diet and was losing weight from the workouts she was doing, said she didn't experience any pregnancy symptoms, but had an inkling that something was wrong when she couldn't sleep.

She went to the doctor who told her she was five and a half months pregnant.

"I didn't believe him. I'm like, 'I'm not showing, there's now way,'" she said.

Her husband shared the happy news on Instagram with a video of his wife's ultrasound.

"Sometimes life blesses you with little surprises," he wrote in the caption.

But amid their joy, the couple is aware that with Lauren's medical conditions and her age, she's at high risk.

To prepare for their baby on the way, the couple, who are already parents to two kids -- son, Odin, 4, and daughter Saoirse, 1, are trying to keep their household as calm as possible.

"She was high risk before and now with everything else, the stresses of the outside world, we're just trying to make sure that we keep a nice, healthy and peaceful household," said Nick, who is off tour for the first time in more than a decade.

As they await the arrival of their new bundle of joy, the family is spending their quarantine together in Las Vegas and looking forward to what the future holds.

"I look at it like, you know, 2020 has had a lot of ups and downs for a lot of people in the world," said Nick. "And for 2021 and coming into the new year, it's just a glimmer of hope … It's just a blessing for me."