Kelly Clarkson got sick during season 20 of, she knew just who to turn to!The singer, Emmy-winning talk show host and coach fell under the weather during the filming of the season 20 Battle Rounds, and last week, her celebrity substitute was revealed to be none other than....Kelsea Ballerini!«Just pretend I'm Kelly,» the country star said in a promo for the season 20 Battle Rounds, proving that she's got Kelly's spark when it comes to landing steals taking shots at fellow coach Blake Shelton: