There's been a major switch-up in The Voice's Season 20 Battle Rounds coaching lineup: Kelly Clarkson is out sick, and filling in for her is none other than Kelsea Ballerini.

Ballerini's surprise appearance was revealed during the latest episode of the show on Monday night (March 22), as host Carson Daly explained that Clarkson was under the weather and would have to tune into the Battle Rounds from home. However, before she left, she tagged in Ballerini to take her place: A substitution that surprised fellow coaches Blake Shelton, John Legend and Nick Jonas when they saw her sitting in Clarkson's chair.

"Just pretend I'm Kelly!" the "Hole in the Bottle" star says in a clip of her appearance on the show, seen below.

"Who do we blame when you make a mistake?" responds Legend.

"Her!" Ballerini replies.

The singer also quickly jumped into The Voice's time-honored tradition of coaches talking smack about each other. "Hey Blake, have I ever told you that you look like my dad?" she jokes from her red chair.

On social media, Ballerini admits that it was an honor to fill in for someone who she's long considered a musical hero. "When [Clarkson] calls and asks you to keep her seat warm, you put all those years of being her superfan to work," she says, adding that she's "forever #teamkelly."

Before The Voice coaches learned that Clarkson was out due to illness, they were confused about her absence, and Jonas joked that she was "probably on her talk show." Some fans were confused as well, as Clarkson had been present on a new episode of the Kelly Clarkson Show that aired earlier in the day.

But Newsweek clarifies that The Voice pre-recorded its Battle Rounds, while Clarkson's syndicated talk show films daily. The current season of The Voice began filming in October 2020, meaning that Clarkson's illness likely occurred late last year.

The Voice airs on Mondays and Tuesdays at 8PM ET on NBC.

WATCH: Has The Voice Changed Blake Shelton?

 The Voice Stars, Then + Now:

More From 98.1 KHAK