Shelton teamed up with Ian Flanigan and Jim Ranger on Tuesday's season 19 finale.
"America, I'm giving you the gift of two duets this year," Blake joked with his team members, Jim Ranger and Ian Flanigan, ahead of the performances. "I had kind of made the decision that I was only gonna sing duets with Gwen Stefani. So I am making a huge exception here for the both of you."
"I was just hoping to sing in front of you, when I came here," Jim marveled. "And now I get to sing with you! This is spectacular."
"If that don't put you in the Christmas spirit," Blake noted, to which Ian finished, "Nothing will!"
First up was Ian, who lent his signature gravelly tone to a performance of Willie Nelson's "Mammas Don't Let Your Babies Grow Up to Be Cowboys" with Blake.
During Monday's live show, the Saugerties, New York, troubadour took the stage to perform a new-school country classic, "In Color" by Jamey Johnson, and a nostalgic original single, "Never Learn."
"I don't know if Ian is from the past or from the future," Blake praised after his performance. "I can't think of where he belongs, there's never been anyone that sounds anything like him. Even though you're new, it's iconic sounding. It's truly amazing, man."
Next up was Jim, who paid tribute to his hometown on a duet of Buck Owens and Dwight Yoakam's "Streets of Bakersfield" with his coach.
During Monday's live show, the soulful pastor and family man impressed coaches and fans with a new original song, "Last," and a show-stopping cover of Joe Cocker's "A Little Help From My Friends."
"Your heart comes through everything that you sing and everything that you do," John Legend raved. "You connect to what you're singing in a way that is really felt by everybody that listens to it."
Ian and Jim have wowed coaches and fans all season -- from Ian's distinct covers of classics like Bob Dylan's "Make You Feel My Love" and Sarah McLachlan's "Angel" to Jim's soulful, emotional renditions of Tim McGraw's "Humble and Kind" and Harry Nilsson's "Without You"-- and now they've got a shot at winning their coach yet another Voice title! (This will be eight for Blake, but we're sure he'll stay humble about it.)
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.