Carrie Underwood + Hunter Hayes

Since winning the fourth season of American Idol in 2005, this 29-year-old Oklahoma native has become one of the biggest names in country music, thanks largely to rowdy tough-chick anthems such as “Before He Cheats." Expect to hear plenty from Underwood's recent No. 1 smash, Blown Away. Getting things started is young Louisiana country-pop heartthrob Hunter Hayes.