Gwen Stefani Recalls 'Bawling' Watching Son Kingston, 17, Perform at Blake Shelton’s Music Venue (Exclusive)

Gwen Stefani is her son Kingston Rossdale's biggest fan.

Last month the Voice coach's eldest son (with ex-husband Gavin Rossdale) was filmed performing a surprise solo set at stepdad Blake Shelton's bar and music venue, Ole Red, in Tishomingo, Oklahoma.

In PEOPLE's latest cover story, the former No Doubt rocker, 53, says watching Kingston perform publicly for the first time was a nostalgic and emotional experience for her.

"King has been writing a bunch of amazing songs. When it's your kid, it's like, you love everything, but this is next level to me. These are really good songs," Stefani says of his songwriting talent. "So Blake said, 'Hey, we got to go live now.' It's so different than writing a song — being able to sing live is a whole 'nother thing."

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Kingston was game, and in a viral clip from his performance, the star-in-the-making was seen chatting confidently with his audience and hitting impressive high notes.

"I was bawling. It's crazy when you have children, and they learn what their gift is. You see their talent, and you're like, 'Wow.' I'm so happy for him that he has that outlet," says Stefani.

"I think back to when I was in No Doubt, and I was exactly his age when [the band] got together. I wasn't even baked at all yet! I was still raw, and had no idea what I was going to do."

Reflecting on her rise to fame in the late '90s and 2000s, the star says her experience was bittersweet.

"I took Kingston on a world tour [when he was 9 months old]. We did 120 shows. I would have to nurse him and then get on stage, and then come off and he would twirl my ponytail," she recalls.

"If I could say I regretted something, I would say that I wish that I could have divided it because that time is so precious. That's when things got really hard for me emotionally because you just don't want to miss anything," continues the singer, who's also mom to Zuma, 15, and Apollo, 9. "But at the same time, you also don't want to let go of this momentum."

At the time, Stefani powered through with a personal goal in mind. "When my kids were teenagers, I really wanted to make sure that I was home there for them — and here we are," she says.

While juggling her career (aside from The Voice and music, she also launched her makeup brand, GXVE, in March 2022) and family still has its challenges, having Shelton, 47, by her side has made the watershed moments all the sweeter.

"What makes me feel the most joy is the successes as a parent, and also as a parent — meaning with Blake — because we're doing this together," she says. "It's these little milestones where you look back and you go, 'Wow, look at where we're at now.' It's the greatest thing ever."

For more on Gwen Stefani's return to The Voice and her life now with Blake Shelton, pick up the latest issue of PEOPLE, on newsstands Friday.