By Brandy McDonnellOklahoma country music superstar Blake Shelton and his pop icon girlfriend Gwen Stefani - who are friendly rivals as coaches on the hit NBC show "The Voice" - have teamed up for a new collaboration called “Nobody But You.” Described in the press materials as a "tender duet," it is one of the five new tracks on Shelton’s upcoming album "Fully Loaded: God’s Country.Read more on NewsOK.com