The Voice Season 8 knockout rounds kick off tonight, March 23, and the show's YouTube channel uploaded two new sneak peek clips of what's going on with the coaches and advisor Nate Ruess.

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Ruess and Blake Shelton have a bit of an odd heart-to-heart in the first clip that is below.

They are both drinking ice water as Shelton compliments fun.'s frontman's physique.

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"You seem like a very fit, healthy person," Shelton reveals to Ruess.

Ruess goes along with Shelton's compliment and shares, "Next to you like it's tough to be tall and thin."

Shelton then makes fun of himself as he asks Ruess, "Which one of my chins were you looking at just then?"

Ruess erupts into laughter as Shelton continues on his little rant, which includes him asking Ruess, "You think I look like a pelican, don't you?"

"Has someone called you a pelican before?" Ruess asks, which leads to Shelton sharing he has read tweets on Twitter that state it.

Another mean tweet Shelton has received is "Blake Shelton got fat, bro."

Ruess' reaction to Shelton's reciting of that tweet is priceless.

Then, in the other clip, which is also below, Christina Aguilera gets sassy with Shelton.

Shelton is talking about Aguilera's contestant Sonic after her knockout round performance.

"For some reason Sonic seems more in Christina's wheelhouse to me," Shelton shares, which cues Aguilera's sass.

"Why is that?" she asks, which gets Shelton a tad flustered as he explains himself.

He insists that Sonic sings more along her own style of singing.

Aguilera really ruffles Shelton's feathers when she asks what style.

"The style of awesome," is his response, which leads to Aguilera laughing.

Tune in on Mondays and Tuesdays starting at 8 p.m. ET for Season 8 of The Voice on NBC.

Tags: The Voice television nbc Blake Shelton Nate Ruess