Brian Urlacher, former Chicago Bears linebacker, and Doug Fister, Washington Nationals pitcher, sing "Let It Go" from the Disney movie, "Frozen," during a USO Holiday Troop Visit to Royal Air Force Mildenhall, England, Dec. 10, 2014. This show was part of a USO tradition to partner with senior leaders and celebrity entertainers to visit troops serving abroad during the holiday season. (U.S. Air Force photo by Airman 1st Class Trevor T. McBride/Released)