Blake Shelton received a sweet Christmas present from Carrie Underwood and fellow The Voice coach John Legend. The two powerhouse vocalists joined their voices to cover Shelton's career-launching single, "Austin," and Shelton himself chimed in on how much he enjoyed it.

Underwood was on set to perform her Christmas duet "Hallelujah" with Legend during the season finale of The Voice, which aired on Dec. 14. Ahead of the finale, she joined Legend on his behind-the-scenes show, Trailer Talk. After a brief chat about her career, Christmas album and her advice for contestants on the show, Legend says he feels like the two of them should sing something country.

"I know that this show is all about friendly competition amongst the judges and I feel like because you can sing anything, I would love to hear your voice on something country," she agrees. "So I think we should sing a Blake Shelton song and you should show him how it’s done.”

Jump to the 8:30 mark in the video below to hear their cover.

"Austin" gave Shelton his first No. 1 hit when he released it as the lead single from his debut album in 2001. Legend accompanies himself and Underwood on a simple keyboard for their version. The two trade lines before harmonizing on the chorus.

Shelton shared his approval in the comments, writing, "Damn y'all.."

Season 21 of The Voice wrapped on Tuesday, Dec 14 with Girl Named Tom crowned as the winner. The siblings, representing Team Kelly Clarkson, are the first trio to win in the show's history.

The finale was a star-studded event. In addition to Underwood, Walker Hayes, Jennifer Lopez, Coldplay, Keke Palmer, Tori Kelly, Ed Sheeran, Alicia Keys, and Kid Cudi all performed throughout the night.

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