"Little Drummer Boy" by Johnny Cash with Neil Young

Found this just now. Anyone know where it came from? I can't find any official release containing this version. Cash originally did it in 1959 but this would have been considerably later than that.

After further investigation it appears it comes from Seven Gates: A Christmas Album by Ben Keith and Friends, which features Neil Young on organ and guitar and a version of "Little Drummer Boy" with vocals by Cash.