Fans of the Hollaback Girl singer were in for a treat at the Forum in Los Angeles when Shelton showed up onstage, and so was Gwen, who appeared initially speechless as her man walked out.
"Stop it, let's take a moment here," she said. "This right now is a miracle, OK? For me. I cannot believe you're here, I'm seeing you right now in L.A., and this is happening!"
Smiling Shelton and his girlfriend of a year then performed a rendition of their duet Go Ahead and Break My Heart, which they first sang together on U.S. talent show The Voice.
The romantic pair met on the music competition series and began dating last year (15) after their summer divorces.
Gwen's oldest son, Kingston, also made an appearance onstage at the Forum. He stood just offstage and cheered his mum throughout the gig, according to ET Online, and he joined her as she took a bow towards the end of the gig.
Earlier in the evening, Gwen's opening act, rapper/singer Eve, also performed with her, singing their duets Rich Girl and Let Me Blow Ya Mind.