VIDEO: Sasha Allen Turns 'Sasha Fierce' on THE VOICE

Dressed in a shimmery yellow evening gown, Sasha Allen belted out her 'Contestant's Choice' number, Aretha Franklin's "Ain't No Way" on last night's THE VOICE. Judge Adam Levine, still groaning over his decision to let the superstar go, called it her best performance "by far," while Usher called her an "incredible" vocalist.

Yet the best was yet to come when Allen took on Carrie Underwood's "Before He Cheats". During the number chosen by her mentor Shakira, the singer tore off her long dress to reveal a sexy black outfit with over-the-knee boots. "What guy doesn't like it when a girl rips her dress off -- especially on the stage," raved judge Blake Shelton, as Usher gushed, "I guess there's more than one Sasha Fierce! You've got an incredible voice and that was really remarkable. I didn't see it coming at all. It was out of here."

Check out both performances below!

The Voice airs Monday and Tuesday at 8 p.m. ET) on NBC.

Sasha Allen has been a backing vocalist for Grammy winners Alicia Keys, Christina Aguilera, John Legend, and pop star Leona Lewis. She portrayed "Dionne" in the Tony Award-winning revival of the hit Broadway show Hair: The American Tribal Love-Rock Musical at the Al Hirschfield Theatre in New York City, and continued with the original American cast to the Gielgud Theatre on the West End in London.

Currently, she is working with acclaimed choreographer and director Bill T. Jones on his new musical, Superfly, produced by renowned record executive Tommy Mottola, the Mottola Group, and the Dodgers.