BlackJack was a fictional band created for this film, with Tony Ljungström playing singer and guitarist Mats, as well as singing the songs on the soundtrack. The year after the premiere Ljungström asked for and got permission to use the band name for a real band in which he was to be the singer, with the rest of the members being unrelated to the film. More than 25 years later the band is still around, with some of the songs from the film being among their most popular.
The giant Yule goat figure made of straw that is set on fire in this movie is the famous 'Gävlebocken' (Gävle goat). It is erected annually in Gävle as a Christmas tradition. It is illegal to burn it down but it's actually a real "tradition" that some people do it from time to time.