In the PBS "American Masters" doc on Bing Crosby - coming in December - there is discussion of the Crosby/David Bowie duet of Little Drummer Boy by both the director and head writer for the Crosby Christmas Special where it occurred. Bowie showed up (because his parents loved Crosby) and was told they would sing LDB as a duet. Bowie refused as he hated that song and felt it was too religious. The writers quickly re-wrote the number so that it is Bing singing LDB and Bowie is singing a different song at the same time. More on the Crosby documentary later. Steve Ramm