Gwen Stefani delivered an emotional rendition of her new single "Used to Love You" on Monday's live episode of The Voice, and her dynamic performance brought her fellow coach and boyfriend Blake Shelton to his feet for a standing ovation.

The 46-year-old singer looked simply stunning in a long, flowing white gown, which evoked the striking elegance of a wedding dress. Backed by several willowy, white trees and engulfed in soft, white fog, Stefani's touching performance was heavenly.

WATCH: Blake Shelton Says He's 'Thankful' for His 'Stunning' Girlfriend Gwen Stefani

As Stefani's song came to a close, the entire audience exploded in a chorus of cheers, but no one seemed more excited than Shelton, who was absolutely beaming as he gave his new girlfriend a round of proud applause.

Shelton spoke with ET before Monday's live episode, saying he was "thankful for Gwen for tons of reasons." The country crooner even teased the striking white gown Stefani wore, calling it "stunning" and "beautiful."

Stefani recently performed "Used to Love You" -- which the singer released just months after splitting with her husband of 12 years, Gavin Rossdale -- during the American Music Awards on Nov. 22.

WATCH: Gwen Stefani Wows the AMAs With Heartbreaking Performance of 'Used to Love You'

Rocking a sheer, black dress and her hair slicked back, her appearance at the AMAs was starkly different than her angelic performance on The Voice.

Check out the video below to hear more from the 39-year-old Shelton on why he's thankful for his new girlfriend and TV co-star.

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