Gwen Stefani Joins Boyfriend Blake Shelton on Stage at L.A. Concert as Her Sons Have Fun Backstage

Gwen Stefani and her sons had a blast at Blake Shelton‘s Los Angeles concert.

On Saturday, the singer, 50, shared a selfie with two of her boys — Kingston, 13, and Zuma, 11 — and boyfriend Shelton, 43, at the country star’s L.A. show at The Forum as part of his Friends and Heroes Tour.

Stefani also surprised the audience when she joined Shelton on stage to perform their duet “Nobody But You.”

“@blakeshelton thank u for having me on your @theforum stage and giving me the opportunity to wear denim and diamond Fringe with a unicorn ponytail 🦄@officialdanilohair@danielxdiamond#neverinmywildestdreams#nobodybutyou 2020 Gx,” she shared on Instagram, posting a photo from the performance.

The mom of three rocked a sparkly denim look, complete with diamond fringe detailing. Her custom Daniel Diamond jacket had “Blake” embroidered on the back and she paired the look with thigh-high sparkly boots.

Stefani, who shares her three sons with ex-husband Gavin Rossdale, also documented the fun family date night on her Instagram Story, sharing several silly videos of herself and her boys enjoying the show and exploring backstage. Her youngest son, Apollo, 6, was also in attendance.

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Shelton teased Stefani’s surprise performance a few days prior to his Saturday show, sharing a video of the couple previously performing their duet together.

“Friends, heroes, AND… @GwenStefani! Y’all never know what might happen on the #FriendsAndHeroesTour!” he captioned the clip on Instagram.

The couple dropped “Nobody But You” — their first duet together — in December, as part of Shelton’s album Fully Loaded: God’s Country.

In January, they released a music video for the love song, which featured several clips of the couple singing while cuddled up on the couch with their dog Betty, goofing around during a late-night dinner date at a casual restaurant and driving around in their car.

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Multiple sources have told PEOPLE that Shelton has become a strong male figure to Stefani’s sons throughout their four-year relationship, and has also had a large part in raising the boys over the last few years.

“He’s so fun and has shown Gwen’s kids another side of life filled with adventure,” a friend of the Voice coach previously said. “The boys have really grown immensely by spending time with Blake.”

Stefani also revealed last year that the “God’s Country” singer is a huge help when it comes to looking after her boys.

“He is a good dad, actually,” Stefani said in early 2019 on the Today show. “He’s been helping me out a lot. I literally get to the point where I’m like, ‘You gotta get home—I need help!’ It’s hard. I got three boys.”