Bob Marley’s “One Love.” The judges’ stunning harmonies with Blake Shelton ’s guitar and John Legend ’s piano spread positivity and joy. The video starts with Legend walking down the sidewalk when he stumbles upon a piano that says “play me.” Legend starts the melody before Kelly Clarkson pops out of a window followed by Shelton and Gwen Stefani. The video ended with on-screen text that says “Together Again” in references to the four judges being on the same season again.