'The Voice': Ruby Leigh Impresses Reba McEntire and Wynonna Judd With Her Cover of 'Blue'

The 16-year-old country singer wowed the coaches once again on Monday's Knockout Rounds.

Ruby Leigh has been impressing the coaches every since her Blind Audition on this season of The Voice, and on Monday's Knockout Rounds, she also won over season 24 Mega Mentor Wynonna Judd!

The 16-year-old singer took the stage alongside two of her talented Team Reba counterparts, Ms. Monet and Rachele Nguyen for a Three-Way Knockout that had all the coaches struggling to pick a favorite.

However, before she even performed, Ruby's rehearsal had Reba and Wynonna geeking out over the young singer's talent and retro country sound.

"Ruby is 16 -- oh my gosh!" Wynonna marveled. "Something there is very spectacular, and I think she's got  such a a future. She's unique in a way that country music needs." 

Ms. Monet also impressed with her rendition of The Emotions' "Best of My Love," and Rachele, just 17, also earned praise for her cover of Maddie & Tae's "Die From a Broken Heart," but Ruby's undeniable talent won over all the coaches from the start -- and Reba sent her onward to the Playoff Rounds.

"Ruby, you're on a different planet," Niall Horan said. "It's amazing what you do with your voice and the power that comes out of it."

"Everything about you is original, yet you just remind us of something so classic," Gwen Stefani agreed, while John Legend called Ruby and Reba "a match made in heaven."

ET spoke with Gwen ahead of this season's Battles, where she opened up about how surreal it is to return to The Voice without hubby Blake Shelton by her side. The Cowboy departed the NBC singing competition earlier this year, after 23 seasons.

"It feels kind of like [my] first season, before I knew he existed," she shared. "It's kind of weird, but it's also like, I'm having so much fun."

"Like, I'm only here because it's fun," Gwen added. "The coaching and actually getting to know your team after the Blinds is my favorite thing, 'cause it's like, the dream's there."

She admitted, however, that it is a little nerve-wracking to look to Blake's chair and instead see The Voice's newest coach -- the Queen of Country herself.

Of how Reba's handled her first season so far, Gwen recalled the Blind Auditions with a laugh.

"She did great. She didn't have to do anything," she remembered. "She'd be like, 'I think you were great. I'd love to have you on my team,' and then they'd be like, 'I pick you!'" 

The Voice airs Mondays at 8 p.m. PT and Tuesdays at 9 p.m. PT on NBC.

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