Their fans went crazy when the 40-year-old "God Gave Me You" hitmaker joined Stefani, 46, onstage in Dallas, reported E! Online.
Shelton performed "Go Ahead and Break My Heart" duet with his lady love.
A fan shared an online video footage in which Shelton is seen playing guitar while Stefani is singing.
As he prepared to leave the stage, the "Used to Love You" songstress hugged him tight and greeted with a kiss.
Shelton and Stefani started dating last year and went public about their relationship after Shelton's divorce from Miranda Lambert.