WATCH: A Great Big World Perform 'Say Something'


Fresh off their career-making performance of Say Something on The Voice this week with Christina Aguilera, A Great Big World has plenty more reasons to celebrate.

In addition to trending worldwide and earning the adoration of the music community with tweets from Aguilera, One Republic, Christina Perri and Cee Lo Green among others, their breakout single has now made it's way to the top of the iTunes Charts as the #1 most downloaded song in America.

WATCH: Xtina Lends Her Voice to 'Say Something'

ETonline scored a special acoustic performance of Say Something, the first performance of the song since their show-stealing appearance on The Voice.

Right now, listeners who pre-order A Great Big World's album Is Anybody Out There? receive downloads of the single featuring Christina Aguilera, the original version of Say Something, and This Is the New Year.

VIDEO: Behind the Scenes with Christina Aguilera & A Great Big World