Birthday boy Blake Shelton, who turned 40 on Saturday, June 18, celebrated with girlfriend Gwen Stefani in front of a crowd of country music fans.

Birthday boy Blake Shelton, who turned 40 on Saturday (June 18), celebrated with girlfriend Gwen Stefani in front of a crowd of country music fans. Stefani showed up onstage with Shelton at Country Jam in Grand Junction, Colo., for a surprise duet Saturday night – and she later returned for a solo performance.

Gwen Stefani Wishes Blake Shelton Happy Birthday With Cute Photo

Shelton and Stefani performed “Go Ahead and Break My Heart” together, off of the country singer’s If I’m Honest album.

“I guess if I had one birthday wish for me personally … I wish I could rock,” Shelton said before Stefani returned to the stage to sing No Doubt’s Rock Steady single “Hella Good,” according to Taste of Country. “I wish I was one of those type of artists that could rock but I can’t … For my birthday I wish I could hear an artist who could rock, that’s my birthday wish.”

“I possibly witnessed the coolest and craziest thing of my life tonight…. Thank you Colorado and @gwenstefani!!! Look up the videos!!” he tweeted after the show.