VIDEO: Jimmy Fallon, Paul McCartney and “Sing” Cast Perform “Wonderful Christmastime” (A Cappella)

From The Tonight Show with Jimmy Fallon – Jimmy and The Roots join Paul McCartney, Matthew McConaughey, Reese Witherspoon, Scarlett Johansson, Seth MacFarlane and Tori Kelly for an a cappella rendition of “Wonderful Christmastime.”