Reba McEntire and Kelly Clarkson Cry in Emotional 'Voice' Rehearsals

Season 23's Mega Mentor brought all the emotion to Monday's Knockout Rounds!

Reba McEntire is The Voice's season 23 Mega Mentor, and she brought all the emotions as the Knockout Rounds kicked off on Monday.

The country music legend -- back again after mentoring Team Blake in the competition show's very first season back in 2011 -- joined coaches Blake SheltonKelly ClarksonNiall Horan and Chance the Rapper and their teams to help bring some big feelings, onstage and off.

It was a Team Blake singer who first brought Reba to tears, as Kylee Dayne wowed the star with her powerhouse rendition of Celine Dion's version of "All by Myself."

"You really touched my heart," Reba told Kylee after her rehearsal. "That's the biggest thing, is to capture somebody in the audience, to where they're sobbing, or laughing. Get some emotion out of them -- and you did it for me."

For Kelly, it was her newest team member, Kala Banham, who brought the waterworks immediately as she rehearsed for her performance of Goo Goo Dolls' "Iris."

"The emotions that she showed, I got chills, Kelly cried," Reba marveled. "That's what you want from a performer."

"Kala surprised me the most," Kelly agreed. "She can make you cry after the first three notes -- that's rare!"

Reba previously revealed that she'd turned down an offer to become a coach on The Voice, explaining that she didn't want to be tied down to a long-term project when she has so much on her plate already. When ET spoke with her earlier this month, we asked if she had reconsidered, now that Blake was stepping away from the show.

"To fill Blake's chair? Wow. That's gonna be tough," she answered coyly. "He did a great job and kudos to him."

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