It may be a classic, shared time and time again each year at Christmas, but David Bowie and Bing Crosby’s duet of “Peace on Earth/Little Drummer Boy” almost didn’t happen.

“If I have to sing that song, I can’t do the show,” a young Bowie told PBS writers when they informed him he would be performing “Little Drummer Boy” along with Crosby on the 40’s crooner’s Christmas special.

In order to salvage the arrangement, the duet became a combination of “Little Drummer Boy” and a newly written tune called “Peace on Earth”.  Hear the full story below.