The 15-year-old fan favorite stood in for Blake Shelton on 'You Make It Feel Like Christmas!'
During Tuesday's season 19 finale of The Voice, Gwen was joined on stage by her finalist, 15-year-old Carter Rubin, and the pair performed "You Make It Feel Like Christmas" off of her 2017 holiday album of the same name.
"How big are the shoes, 'cause I've heard he's really tall?" Carter joked of filling Blake's shoes on the duet
"I am excited to sing with Carter, because he's so unbelievably talented and he's gonna make me look really good," Gwen raved of her fan-favorite crooner.
"She's been such an excellent coach from day one, and I can't believe I get to sing with her," Carter added. "I'm so excited!"
During Monday's live show, Carter took the stage to perform a stunning cover of Miley Cyrus' "The Climb" and an original single, "Up From Here," which made Gwen emotional, not for the first time this season.
"I'm so happy for you," his coach raved. "You're unbelievable, you're just so calm, and it feels like you're just meant to be doing this, and I know that America's gonna see that tonight."
Rubin has wowed Voice fans, and Gwen in particular, all season -- from his powerful Blind Audition performance of Lewis Capaldi's "Before You Go" to his covers of Mariah Carey's "Hero" and The Muppets' "Rainbow Connection" that brought Stefani to tears -- and now he's got a shot at landing his coach her first-ever Voice championship.
The Voice crowns its season 19 winner on Tuesday night, starting at 8pm PT/ET on NBC. See more from this season in the video below.
'The Voice': Watch the Finale Performances from Jim Ranger, Carter Rubin, DeSz, John Holiday & Ian Flanigan