Bridget Kelly, on stage, a Grammy-winning singer and songwriter, performs for U.S. Service members during the 2013 USO Chairman's Holiday Tour at Bagram Airfield in Parwan province, Afghanistan, Dec. 9, 2013. The 2013 USO Chairman's Holiday Tour was a seven-stop, four-country troop visit led by Chairman of the Joint Chiefs of Staff U.S. Army Gen. Martin E. Dempsey. In addition to Kelly, the tour included "Duck Dynasty" stars Willie and Jep Robertson, Washington Nationals first baseman Adam LaRoche, former New England Patriots offensive tackle and three-time Super Bowl champion Matt Light, actor and comedian Thomas "Nephew Tommy" Miles and former correspondent for NBC's "The Voice" Alison Haislip.