"It's very basic," Joel Smallbone, 36, tells PEOPLE, explaining how he and his brother cracked the "Little Drummer Boy" code. "This is a song about a boy who's playing a drum for Jesus.

"Little Drummer Boy" is only one of the many exciting performances set to be featured on the episode, premiering on Dec. 12 at 10 p.m. ET.

The Little Drummer Boy features amazing stop-motion animation that helped pave the way for animated films to follow. It was made by the same people who brought you Frosty the Snowman, Rudolph, and ...

Peace On Earth / Little Drummer Boy went on to become one of Bowie's most successful and fastest-selling singles, with sales of over 250,000 within its first month, which led to it being certified ...

Dressed like a toy soldier, Jeong delivers his rendition of the Christmas classic "Little Drummer Boy," while giving extra emphasis to the "Pa-rum-pum-pum-pums." You can sing along, with help from ...