The pair performed "You Make It Feel Like Christmas," which is both the title of Stefani's special and the title of the song they share on her recently-released holiday album.
Shelton donned a black suit and sparkling black tie as he grabbed a guitar to perform the song, while Stefani was feeling festive in a red plaid ensemble. The duo was joined by a group of dancers and a horn section to add even more flair to the track.
During the song, the loved-up pair couldn't keep their eyes off of each other, sharing a sweet hug after finishing their performance.
Shelton appeared on the special again with a cameo in a sketch with a younger Stefani proclaiming, I hate country singers. They're really annoying," before Shelton convinced her otherwise with some mistletoe.
"Yay!! It was incredible to write with @BlakeShelton & share the stage for a song that is so joyful & Christmas-y!" Stefani tweeted after the special, adding the hashtag #LuckyGirl.
Shelton previously told PEOPLE that he helped Stefani write the tune, sending her a melody for the chorus and some lyrics he had come up with.
"I just wanted to throw something in the mix to keep that project moving and she said 'No, no, no. You're gonna sing these words to me and I'm gonna sing these words to you,'" he explained. "She had it all mapped out and I couldn't have been more honored or more proud to be on one of her records."
Photo Credit: YouTube / GwenStefaniVEVO