Kelly was fuming while watching Guy's team members Bukhu Ganburged and Johnny Manuel perform an "unfair" song with the Mongolian-Australian throat singer and the musical theatre singer performing Earth Song by Michael Jackson.
The argument kicked off with judge Delta Goodrem saying she believed the song only suited Johnny's voice and not Bukhu, something Kelly quickly agreed with.
Delta said: "I mean, I'm trying to work out, because – firstly, clearly Johnny, you're in the zone, it was flawless what you were doing. The only thing I was struggling with was I was trying to understand how this was a battle. Because it felt like Bukhu was your backing player.
"Bukhu, I didn't get to hear any of your vocals that I heard, that I know we all turned around for in the Blinds and I didn't at all feel it was fair. So, I'm confused how Bukhu felt in that situation because he was backing you. And that's it, and that's not a battle and that's not fair."
When asked if she agreed, Kelly said: "I do agree, Johnny the way you performed that was so beautiful... It's so unfortunate because I feel like it takes away from both of you in this moment, because Johnny can't just relish in this incredible moment."
Kelly told Guy that she took that moment away from Johnny because she chose a song where Bukhu was only backing up.
To which Guy responded: "You guys have lost your minds."
Kelly explained that the battles weren't meant to create great moments, but instead showcase vocal strength.
"Right now we are in a battle and it is about giving a song that is fair to both artists. That's it," she said.
The argument continued with Kelly choosing to walk off the stage, saying: "I just feel like this is becoming redundant and I'm not going to do this."
And social media users agreed with her with one user writing: "Honestly, sidelining a singer who represents a different culture/style and putting them in the background of a more western style singer feels extremely discriminatory. Pathetic. Absolutely pathetic. Poor show Guy."
Another added: "Delta is 100% right. I don't think the song choice was the issue, it was the arrangement. There simply wasn't a fair opportunity for both singers to shine..."
"It’s not hard to just give Bhuku lines, Guy!!! Yes we wanted to hear Bhuku sing more,” another fan said.
I was sitting here wondering when we were going to hear Bukhu sing - then we get a tiny bit, but the rest was him playing his instrument - isn't the show called "The Voice" #thevoiceau
— Rae (@RaeRaeM) June 21, 2020
Maybe an acoustic arrangement with more lines to Bhuku wouldve been fairer.
Even when Bhuku tried to throat sing, the electric guitar was too loud and drowned him out. he only got 15% of the vocal lines , 85% to other guy #theVoiceau
— shorey (@shoreytime) June 21, 2020
#TheVoiceAU Delta is 100% right. I don't think the song choice was the issue, it was the arrangement. There simply wasn't a fair opportunity for both singers to shine...
— Isobel (@isobel_saccaro) June 21, 2020
It’s not hard to just give Bhuku lines, Guy!!! Yes we wanted to hear Bhuku sing more!! #TheVoiceAU
— Domonique (@_domchantal) June 21, 2020
Honestly, sidelining a singer who represents a different culture/style and putting them in the background of a more western style singer feels extremely discriminatory. Pathetic. Absolutely pathetic. Poor show Guy. #TheVoiceAU
— b (@svrvivesomehow) June 21, 2020
Pretty sure there would have been a way for Guy to turn that song into an even battle between those 2. Delta and Kelly are spot on! #TheVoiceAU
— Nat 🐯 (@Natsky1988) June 21, 2020
Is this the voice or the instrument 😂
I feel as if it’s unfair that they were paired and that guy turns for an instrument not a vocal especially when it’s a show about singing 😂
— MichaelMSC 🐐 (@themichaelsc) June 21, 2020
Watch the full exchange here: