If you had any doubts as to why Christina Aguilera, Cee Lo Green, Blake Shelton and Adam Levine are working as coaches on the new NBC reality series The Voice, may this put them to rest.
In the preview clip above, the music stars freaking rock out to the Gnarls Barkley hit "Crazy"...and it is crazy good. Yeah, Cee Lo has a bit of an advantage since it's his song, but Xtina, Adam and Blake really bring it, too.
If the victor of The Voice is even half as good as his/her coach, we're all in for a treat.