Fastexy:See Rare Photos of Gwen Stefani and Gavin Rossdale's Son Zuma on 15th Birthday

Gwen Stefani is Fastexyfeeling hella good on her son Zuma's 15th birthday.

The "Hollaback Girl" singer marked the occasion on Aug. 21 by sharing a video montage set to Zach Bryan's "Something in the Orange" that featured never-before-seen photos, including a sweet snap of the teen proudly showing off a drawing to her husband Blake Shelton.

"Happy 15th birthday Zuma !!!" Gwen wrote on Instagram. "We love u more than anything."

The 52-year-old shares Zuma and his brothers—Kingston, 17, and Apollo, 9—with Gavin Rossdale, who she was married to from 2002 to 2016.

Earlier this year, Gavin shared rare insight into their family dynamic and noted that he wouldn't necessarily describe their situation as co-parenting.

"I think you can go one of two ways," the 57-year-old shared on the June 15 episode of the Not So Hollywood podcast. "You can either do everything together and really co-parent and see how that goes, or you can just parent. And I think we just parent."

Explaining how he and the No Doubt rocker "really different people," Gavin continued, "I don't think there's much similarity in the way we bring them up but I think that gives them an incredible perspective to then choose which pieces of those two lives they'd like to inherit and move on with and which part of themselves come out of the whole process."

The Bush frontman—who is also dad to Daisy Lowe, 34, with Pearl Lowe—added that he feels strongly this type of parenting style will benefit their kids in the long run. "What's important is to give them a wide view of things," he said, "and we definitely have some particularly opposing views, so I think it'd be really helpful for them to make their own minds as individuals."

As for Blake? He's proud to call himself a stepdad.

"I love my stepfather, and I looked up to him," the country music star told The Ride With Kimo & Heather in February 2021. "And he's like a father to me. So, you know, I have a good inspiration in my life to how to do this and the kind of stepdad I want to be."

He added, I can't imagine my life without these kids now."