The frenemies were at each other's throats on Tuesday's episode.
The famous frenemies are reunited for season 23 of the NBC singing competition and have been going head-to-head since the Blind Auditions began -- even when they try to work together against rookie coaches Chance the Rapper and Niall Horan.
Tuesday's show began with Blake pranking Kelly by pouring water in her chair before she sat down -- thankfully, she noticed in time and didn't ruin her dress!
And things only got more contentious from there. After Chloe Abbott took the stage, winning over coach-to-be Chance with her rendition of the Bee Gee's "How Deep Is Your Love," Kelly decided that she'd had it with the way Blake fibs to the contestants, and hooked him up to a lie detector.
Host Carson Daly gave the readout as Kelly peppered Blake with a series of increasingly difficult questions, including "Did you block me this season?" (Blake lied) and "Am I your favorite coach?" (lied again).
"I'm only giving you that because of your wife," Kelly accepted with a laugh.
"It's exciting to have Kelly back because when she's gone, I don't have anyone to truly fight with," Blake told the cameras later. "And when she's here, the fight is on."
However, the two proved that their animosity is all for show when Kelly paid tribute to Blake's final season at the end of the episode.
"Blake is killing it his last season. I suspected that would happen," Kelly admitted. "Don't tell him I said this, but he's, like, The Voice. It's gonna be really weird when he's not here. He will be missed."
"I texted him," Kelly shared. "If he was gonna do a last season, I wanted to make sure I was there."
However, the talk show host insisted that she won't be letting nostalgia affect her competitive nature.
"If [Blake] wins, I am very happy for him, because that is super cool to win on the last season and he's literally the show, from its conception," she conceded. "But, like, I'm not, like, rooting for him to win. I'll be happy for him if he does, but I'm obviously trying to win myself."
As for the show's new coaches, Niall and Chance said they were ready to put in the work against the Team Blake dynasty.
"It's been awesome," Chance said of joining the show. "Kelly's very, very sweet, very nice to me. And Blake is... here."
The Voice airs Mondays and Tuesdays at 8 p.m. PT/ET on NBC.