Jimmy Fallon Enlists Stars to ‘Sing’ Most Polarizing Christmas Song Of All TimeJimmy Fallon Enlists Stars to ‘Sing’ Most Polarizing Christmas Song Of All TimeJimmy Fallon got some help from The Roots and the star-studded cast of 'Sing' for an a cappella version of 'Wonderful Christmastime.'PopCrush StaffPopCrush Staff