The move happened after a heated face-off between two members of John Legend's team: Cami Clune and John Holiday.
To recap, here's how the Knockout Round works: Each coach pairs two singers on their team, but unlike the Battles duets, each contestant selects and sings their own song. Each coach is allowed one steal to save a contestant from elimination. At the start of Tuesday's episode, Clarkson was the only coach who hadn't yet used her steal.
Clune kicked off the round singing a modern, eerie version of Annie Lennox's "I Put a Spell on You." Before the performance, Clune said she wanted to show a more theatrical side.
And she seemed to succeed, with her take on the jazz classic bringing John Legend and Clarkson to their feet.
"You better sang!" Clarkson exclaimed.
But Holiday wasn't going to go down without a fight. Before his performance, he said he planned on tapping into his painful past to bring Celine Dion's "All By Myself" to life.
"As a fan of music and a fan of this show, I want to say I love you," coach Blake Shelton told Holiday after his emotional performance, before quipping, "And, as a coach on this show, I want to say I hate you and that you're an enormous pain in my ass."
Though both singers earned high praise from the coaches, Legend chose Holiday.
"Cammie gave one of the best performances I've seen this season," Legend said. "Her only problem is she's going against John, who sings just out of this world. He is 'The Voice.' "
But don't worry, Clune fans: Thanks to Clarkson, you haven't seen the last of her.
That's because, as Clune was thanking Legend before exiting the stage, Clarkson interrupted with a steal.
"Who cares what he thinks!" the "Stronger" singer exclaimed as she hit her button. "I would like to say thank you to John for screwing up, because you are awesome, and I cannot wait to go through songs with you and see what you're gonna do next."
That wasn't the only Knockout Round from Tuesday's episode. Marisa Corvo and Tanner Gomes, two members of Clarkson's team, also faced off, with Corvo taking on Cher's "If I Could Turn Back Time" and Gomes tackling Tim McGraw's "Real Good Man."
"Oh my gosh, I'm gonna hate myself either way," Clarkson said after the performances, before choosing Gomes as the winner.
For the last Knockout Round of the episode, four previously saved singers competed in a four-way knockout: Team Shelton's Taryn Papa, who sang Faith Hill's "Cry"; Team Legend's Julia Cooper, who sang Billie Eilish's "Wish You Were Gay"; Team Gwen Stefani's Larriah Jackson, who sang Adele's "One and Only"; and Team Clarkson's Ryan Gallagher, who sang Andrea Bocelli and Sarah Brightman's "Time to Say Goodbye."
As for who wins, that's up to you, America.
Host Carson Daly wrapped the episode by reminding viewers to vote for the winner of this final Knockout on the official "Voice" app, NBC's website or through Google Assistant. Voting is open now through 7 a.m. EST Wednesday.
This article originally appeared on USA TODAY: 'The Voice': Kelly Clarkson steals from John Legend in final Knockout