A week after the Destiny's Child star attacked Sebastian on the TV talent show for trying to force her to pick an act he liked when his team for the series was full, she accused Guy of losing his mind before getting out of her spinning red chair and walking away.
The row started when 39-year-old Kelly called Guy "unfair" for asking Mongolian throat singer Bukhu Ganburged and Johnny Manuel to perform Michael Jackson's "Earth Song" together.
Fellow judge Delta Goodrem also criticised Sebastian, saying the tune suited Manuel's vocals but not his fellow contestant's.
"You chose a song where Bukhu is only backing up," Kelly raged. "Right now we are in a battle and it is about giving a song that is fair to both artists. That's it."
"I just want to make great moments," he shot back. "I don't care about the battle element. I care about both of you (Buku and Johnny) shining."
As the argument escalated on the show, Kelly walked off the stage, stating, "I just feel like this is becoming redundant and I'm not going to do this."
Guy refused to back down, adding, " 'Cause a walk-off does heaps. What are you going to do? What's a walk-off going to do? That's so disrespectful."
The show ended and Kelly and Guy are expected to battle on TV again on Monday night's "The Voice" episode.