A representative for the 38-year-old Levine confirmed Gio's birth to E! News, but did not give any further details. Levine posted a photo of a still-pregnant Prinsloo on Instagram for Valentine's Day, though.
Prinsloo and Levine announced they were expecting their second child this past September. Prinsloo posted a selfie showing her small baby bump. "Round 2," she wrote in the caption.
In November, Levine told Ellen DeGeneres that their new baby is a girl, and admitted that Gio will not be the last addition to their family.
"I want a lot. I thrive in chaos. I really genuinely enjoy it," Levine said. He added that Prinsloo is an only child, so she wants to make sure her kids have siblings. "She was an only child, so look out. She wants like 100 babies, but I don't know if I can do that," the Voice coach said.
The 28-year-old Prinsloo and Levine have been married since 2014. Their first daughter, Dusty Rose, is now 16 months old.
"I love Adam, and when you get married and you fall in love with someone, you think that there's no greater love than that love," Prinsloo told PEOPLE last year. "And then you have a baby, and it's just next-level love."
She said the most surprising thing about becoming a mom was finding out what that "next-level" of affection.
"I think I was surprised by that because everybody always tells you that, and you're like, 'Yeah, yeah, whatever.' I see how much more you can love," Prinsloo said. "You think there's a limit to love — like, 'This is the thing that I love the most' — but honestly, I think what surprised me most is how intense that love is, and also how hard, at times, it is."
Levine is the lead singer of Maroon 5, which released their latest album, Red Pill Blues, in November. They plan on touring this year to support the record. He is also still coaching on NBC's The Voice, which returns Monday, Feb. 26.
He has been a coach on every season of the show, along with Blake Shelton. This season, he will be joined by first-time coach Kelly Clarkson and returning coach Alicia Keys.
As for Prinsloo, she is a Victoria's Secret Angel and has walked in every Victoria's Secret Fashion Show from 2007 to 2015. In 2015, she was on Forbes' list of highest-paid models in the world, earning $3.5 million that year.