Gwen Stefani jokingly reminded husband Blake Shelton that they were married after he introduced her to the stage with her maiden name.The pair took the stage on 15 July in Tishomingo, Oklahoma for an impromptu acoustic performance at the ranch Blake owns and where the pair wed on 3 July.In a video, shot by a fan in attendance, Blake welcomed "Gwen Stefani" to the stage where they sang two of their songs, Happy Anywhere and Nobody But You.MORE: How Blake Shelton made intimate wedding to Gwen