Tim McGraw and Carrie Underwood are headlining the Country 2 Country Festival this weekend at London's O2 Arena. One of the year's biggest country music events in the United Kingdom, McGraw headlines Saturday's (March 16) show which also features Little Big Town, Vince Gill and a solo performance by Sugarland's Kristian Bush. In addition to Underwood, Sunday's lineup includes Darius Rucker, LeAnn Rimes and Brantley Gilbert. Following his festival appearance, Gilbert is scheduled to travel to Italy and the Middle East for his first-ever USO tour. Underwood performs Saturday in Belfast, Northern Ireland.