The film adapts parts of two stories from the Astérix comic series: the plot about the false soothsayer is from the 19th album "Le Devin", while the plot of the druid losing his memory is from the 7th album "Le Combat des chefs".
There are two English dubs of this film. An American version and a British version. As if 2014, the British version has not been released on DVD. Only the American version is available in the UK.
Despite the film's title, only a minor section of "Asterix and the Big Fight" features in the plot (specifically, Getafix's amnesia).
While the movie's storyline is mostly adapted from the book Asterix and the Soothsayer, its English distributor refused to use that title out of concern that younger audience members would not know what a soothsayer was, and so would not be interested in the movie.
This is the first movie without the character of Julius Caesar, only it is mentioned by Centurion Voluptuous Arteriosclerosus and Bulbus Crocus.