Carrie Underwood was a guest star on the Season 21 finale of The Voice on Tuesday night (Dec. 14), and she came armed with her powerhouse vocals. Taking the stage with coach and R&B singer John Legend, the two launched into their Christmas duet, "Hallelujah."

With Legend on piano and Underwood on the microphone, both stars had the audience in the palms of their hands and screaming in their seats. The stage, adorned with lit candles, appeared heavenly, as the two artists took turns singing back and forth and showing off their angelic harmonies.

Let the world stand still, the church bells ring / Silent night as the angels sing / Hallelujah, Hallelujah / Let the magic warm the moonlit air / Hear the choirs join in singing everywhere / Hallelujah, Hallelujah,” they sang in unison, bringing the Christmas magic to life in the Universal Studios room in Hollywood, Calif.

Along with Underwood, Coldplay, Keke Palmer, Tori Kelly, Ed Sheeran, Jennifer Lopez, Alisha Keys, Kid Cudi and Walker Hayes also performed during the two-hour finale. Blake Shelton, Kelly Clarkson and John Legend took the stage with the remaining artists from their teams.

“Hallelujah” appears on Underwood’s chart-topping 2020 holiday project entitled, My Gift. The project also features classic holiday tunes like “O Come, All Ye Faithful,” “O Holy Night” and “The Little Drummer Boy,” featuring Underwood’s oldest son Isaiah.

Earlier this week, Underwood performed the final shows of the first leg of her Reflection: The Las Vegas Residency. Her husband Mike Fisher and their two sons, Isaiah and Jacob, made the trip to Las Vegas to catch her on stage.

“Boys are ready!” Fisher captioned a shot of the family seated in the audience.

Watch the video above to see Carrie Underwood and John Legend’s performance of “Hallelujah” on The Voice.

Famous Singers from The Voice, Then + Now

Ten years (and counting) made a huge difference for many of the most popular singers and stars of The VoiceBlake Shelton looks noticeably different, but so do some of country music's most memorable performers.

Winners like Cassadee Pope and Danielle Bradbery wore baby faces when they auditioned during their respective seasons. The same can be said for Morgan Wallen, a forgotten castmember from the show who's transformed more than anyone else on this list of The Voice stars then and now.