A Cosmic Christmas is a 1977 animated short film telling the story of aliens who discover the true meaning of Christmas with the help of a little boy and his pet goose.
I think it's interesting that the aliens look like 3 wise men, their first words are "Do not be afraid" and they come to search for the meaning of "The Bethlehem Star" that shone 2000 years ago. I found it preachy. It was also slow and had too much slapstick-style "physical" comedy to suit me. Maybe if I'd seen it as a child...