When Pentatonix say something, that something's in four-part harmony.

A Great Big World and Christina Aguilera's "Say Something" is SO full of #feelings -- you can imagine how heartbreaking the somber, piano-driven duet would be if it were performed a cappella. Well, imagine no more, because the song just got a passionate "Pitch Perfect" makeover by the YouTube stars of Pentatonix.

The Season 3 winners of "The Sing-Off" tackle the hit with only five voices and a cello. In their more than capable hands (er, throats?), the chorus becomes a swelling plea that's -- dare we say it? -- even better than AGBW and Xtina's already ***flawless original version. #NoShade

Much like we were after witnessing Pentatonix's take on "Royals," we are dizzied, stunned, speechless -- basically ALL the adjectives related to shock. Oh, and we want to give a special shout-out to the cellist on the right who's beatboxing and killing the fretless game at the same time.

Anyway, the clip's already got over 2-million views, so check it out now for the #CoolCred before the rest of this great big world's raving about it.

+ Watch Pentatonix's "Say Something" cover.

Photo credit: Pentatonix/Madison Gate Records via YouTube