The couple performed their holiday hit, “You Make It Feel Like Christmas,” during Stefani’s one-hour holiday program by the same name, which aired on Tuesday evening.
Though the pair only shared a sweet hug following their duet, the mother of three, 48, and this year’s Sexiest Man Alive, 41, couldn’t take their eyes off each other.
Stefani called herself a “lucky girl” on Twitter, writing, “It was incredible to write with @BlakeShelton & share the stage for a song that is so joyful & Christmas-y!”
Shelton made another cameo during his girlfriend’s special, appearing in a sketch in which her younger self jokingly declared, “I hate country singers. They’re really annoying.” The country crooner later enticed Stefani with some mistletoe.
Shelton exclusively opened up to PEOPLE about teaming up with the former No Doubt rocker on the track, saying Stefani called him while he was on the road one day to tell him about writing the song.
“She was so excited,” said Shelton. “I love seeing her that happy. She’s so happy when she’s writing and just hearing that in her voice and how into it she was, I just couldn’t stop thinking about [it] so I got my guitar out and thought, ‘I wonder if I could help her in some way?’”
After writing the melody for the chorus and coming up with some lyrics, Shelton sent her his portion of the song — and it ended up being the first verse.
“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.’ She had it all mapped out and I couldn’t have been more honored or more proud to be on one of her records.”