It's on! Ahead of her first full-time coaching gig on The Voice, Kelly Clarkson is talking a little smack to co-star Blake Shelton. "I'm a big fan of [Shelton]. Always have been for, I don't know, for like a decade now we've been friends," Clarkson told The Chicago Tribune today ahead of her performance this Saturday with Shelton at the Department of Defense Warrior Games' opening ceremony at Soldier Field. "So yeah, it should be fun. But yeah, I guess it will be a precursor for The Voice.