Gwen Stefani bared her soul (and most of her body) during an emotionally-charged performance of her new song “Used to Love You” at the American Music Awards on Sunday.

The 46-year-old singer took the stage in a black patterned cutout dress to perform the breakup ballad, which Stefani released in October, just two months after announcing her divorce from husband of nearly 12 years, Gavin Rossdale.

WATCH: Gwen Stefani on Her Divorce From Gavin Rossdale: 'My Life Blew Up in My Face'

One of the reasons for the divorce is that Rossdale had allegedly been cheating on the No Doubt lead singer for years with the couple’s nanny, a source told ET. Stefani has not publicly addressed the speculation, only commenting recently that “my life blew up in my face.” In September, the Voice coach told ET that music has helped her through the split.

"The biggest gift has been to be able to take some tragedy and write a song about it and share that," she said. "The rewards that I've gotten through that is just unbelievable."

WATCH: Gwen Stefani and Gavin Rossdale Gushed Over Each Other Days Before Her 'Life Blew Up' Over Alleged Affair

The singer was without new squeeze Blake Shelton at Sunday’s awards show, though the country star tweeted his excitement, telling fans to "prepare for greatness" and agreeing with a fan who called Stefani's song the best performance of the evening.

WATCH: Gwen Stefani Says She 'Never Heard Of' Blake Shelton Before She Joined 'The Voice'

Stefani recently opened up about her new relationship on Ellen, where she admitted to never having heard of the country star before they began working together on The Voice.

"Before I was on The Voice I never heard of him before," Gwen told the daytime host. "I’m an O.C. girl! Like, what would I know?"

Check out Stefani’s intensely personal music video for “Used to Love You” below.

WATCH: Gwen Stefani Unveils Intensely Emotional 'Used to Love You' Music Video

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2015 American Music Awards Arrivals