Jimmy Fallon and The Roots Join 'The Voice' Coaches for Epic Mashup of Their Greatest Hits

Sometimes, there's nothing better on a cold night than a musical mashup. A fresh take on the music you love to make you feel warm inside.

"Glee" built a brief empire on that feeling, and now Jimmy Fallon is following suit, joining with the Roots and "The Voice" coaches to reimagine some of the most iconic music of coaches Adam Levine, Jennifer Hudson, Blake Shelton and Kelly Clarkson.

Presented a cappella with Fallon and The Roots providing the vocal instrumentation behind the coaches' vocals, they truly created something unique and totally special.

Presented in grid style like something out of "The Brady Bunch," we loved the playful way everyone played with the presentation, like when J.Hud swatted Adam's box out of the frame, and Blake kept looking at Jimmy, who'd donned a cowboy hat for Blake's country segment.

By the end, all four coaches and even host Carson Daly were involved as the grid expanded to include 16 different performers. The interweaving vocals were more intricate than ever, and yet every beat was hit and it all worked surprisingly well together.

Pentatonix might have a real threat on their hands if The Roots ever decided to compete with them on the a cappella front. We already know they're musical geniuses in their own right, and even with classroom instruments, but here they're proving they don't need instruments at all to bring it.

And Jimmy Fallon, well, we already knew that he was a musical chameleon. Honestly, we've watched this over and over a dozen times already and it's not getting old. That said, we'd love to get some more coach singles into this mashup. Can we do a new edition of this every week that "The Voice" is on the air?

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