Pentatonix Celebrates 'Say Something,' Teases 'Frozen' Cover: 'We Just Might' (Video)

Five singers, three cities, one incredibly sad song -- the electro-infused a cappella quintet tells THR of how their vintage-inspired A Great Big World cover came to be.
Brandon Lyon

Is it still considered an a cappella track if someone is playing a cello? What if that person is also beatboxing at the same time?

Regardless of its classification, Pentatonix's latest video cover of A Great Big World's "Say Something" with Christina Aguilera is pleasing to the ear, as the YouTube upload from the Sing-Off champions has collected over three million views in under three days and a shoutout from the original track's duo.

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"We always want to incorporate the cello, but we have to do it in a very particular way -- our fans love that we do a cappella, but the cello is such a huge part of what we do because that's how we found Kevin [Olusola]," Scott Hoying told The Hollywood Reporter while on a tour stop in Las Vegas. Before competing on season three of the NBC reality competition, longtime friends and harmonic trio Hoying, Mitch Grassi and Kirstin Maldonado added bass Avi Kaplan to the group, and also recruited the beatboxing cellist and viral phenomenon. "And the song is so incredibly sad, and the cello is so good at capturing sad music so perfectly. Plus, it gave him a chance to show off what he can do."

The group, along with producer Ben Bram, arranged the cover in two days -- and actually used a computer program this time, "because normally we sit in a circle and do it by ear, but this is one of those arrangements where we had put it on paper and really figured out the intricacies" -- and only sang through it once before recording.

"We rehearsed it in our hotel room at a gig in Bermuda, and then recorded it when we got back to L.A., and once we got the mix back, we recorded the video while we were in Nashville at a tech rehearsal," said Hoying of the upload, which shows the group in formation with glazed-over faces. "I brought up that I wanted it to be vintage and stark, and to look like one of those portraits that come to life."

VIDEO: A Cappella 'Evolution of Beyonce' Video Goes Viral: Pentatonix on How the Hit Came to Be 

Currently making their way through their sold-out North American tour, Pentatonix breaks out into the ballad after Olusola enjoys a solo moment onstage with his cello -- a set list surprise for concert-goers before the video's release.

Though a crowd-pleaser, the group has yet to upload an a cappella cover of the hits from Frozen. Three of the singers joked around on karaoke versions of the tracks last month, which has left fans begging for a full-fledged rendition.

"We keep getting asked that, and you know, we actually might," revealed Hoying. "We got asked to do a gig where we sing 'Let It Go' and do a full group arrangement of it, and I think we might. Obviously, that movie is huge right now, but when we did it for [our web series] "Superfruit," we only did it because we love it so much -- we saw it together, and we were just having a good time. We had no idea it would turn into kind of a big video. We'll see, we're gonna play it by ear. If we end up having to arrange it for this gig, we'll probably do a video for it too."

VIDEO: Pentatonix Singers Cover Disney's 'Frozen'

Also potentially on Pentatonix's to-do list? Pitch Perfect 2. "We haven't heard anything about being part of it -- we would obviously love to. … There's going to be meetings about it. I know we've talked about it briefly, that we would want to pursue that."

Watch the video below:

Twitter: @cashleelee