Paul McCartney, Jimmy Fallon and the Roots, and ‘Sing’ cast are simply having a wonderful Christmastime

Late-night television’s countdown to Christmas continues. Jimmy Fallon unveiled his most recent a cappella efforts on Tuesday’s “Tonight Show,” tapping the cast of the new animated film “Sing” to cover Paul McCartney’s “Wonderful Christmastime.” The special guests? The Roots and Macca himself.

Reese Witherspoon, Scarlett Johansson, Matthew McConaughey, Tori Kelly and Seth MacFarlane voice various animals with vocal chops on “Sing.”…