All four judges from NBC's upcoming singing competition The Voice are belting out Cee Lo Green's hit song "Crazy" and they sound fabulous!

Adam Levine, Christina Aguilera, Blake Shelton and Cee Lo Green are proving why they're in command of the new show.

As for the premise of The Voice, each contestant's talent will be judged strictly by their voice ... not their looks. The show's executive producer Mark Burnett may have another hit show on his hands!

See the full 12-minute preview of the first episode ... after the jump.