Nick Carter Gushes Over Pregnant Wife: 'I Knew She'd Be the Best Mother'

Monday's Dancing With the Stars proved to be an emotional night for Nick Carter and his wife, Lauren, who learned the sex of their baby-to-be on live TV.

Nick and Lauren were overcome with emotion when, after the musician's amazing dance, co-host Erin Andrews opened up a giant gift box in front of the couple, letting loose a cluster of blue balloons that revealed they are expecting a boy.

Lauren, Nick and his DWTS partner, Sharna Burgess, spoke with ET after the show, and the 35-year-old Backstreet Boy opened up about keeping his wife's pregnancy a secret, and how it felt to share the news this past week.

WATCH: Nick Carter Gets Emotional Over Wife's Pregnancy on DWTS, Learns Sex of the Baby on Live TV

"Honestly, it's been a relief in a lot of ways because I was able to finally tell the world what I'd been feeling and holding inside," Nick explained.

As for the news that they were having a boy, Lauren revealed that they were very excited.

"We obviously wanted a healthy baby but we were hoping for a boy," Lauren, who is 16 weeks into her pregnancy, shared.

She added that they are most looking forward to "teaching him to golf!"

WATCH: They're Having a Baby! Hollywood's Best Celebrity Pregnancy Announcements!

"I knew she'd be the best mother, and that's why I felt comfortable going to that next step," Nick gushed about his wife. "I know she'll help me raise a good boy."

The news of Lauren's pregnancy was revealed during a pre-taped segment, played before Nick and Sharna took the stage. In the short recorded package, the boy band member and his spouse also detailed some of the hardships they've face, including a miscarriage a year ago.

The couple also welcomed cameras into their doctor's office for a look at the ultrasound image of their little bundle of joy.

WATCH: Nick Carter Just Made Every Backstreet Boys Fan's Dream Come True on DWTS

According to Nick, he wasn't even able to watch the segment as it played in the DWTS stage because he knew it would overwhelm him.

"I didn't want to get emotional. I didn't want to cry," said Nick, who teared up after finishing the dance, which earned him the night's only perfect score. "I held it in all the way to the end and I was like, 'Oh God!' and it just kind of all came out. All these different emotions -- from the preparation of the dance to how much work we've had up until this point, to the story itself meaning so much to me. All those things combined made it really emotional for me."

For more on Nick and Lauren's beautiful, emotional night, check out the video below.