Page "The Great Dictator" Paragraph 16

Chaplin's half-brother Sydney Chaplin directed and starred in a 1921 film called King, Queen, Joker in which, like Charlie, he played the dual role of a barber and ruler of a country who is about to be overthrown.

According to Janiss Garza, Chaplin was sued in the 1940s over plagiarism problems with The Great Dictator.

Apparently neither the suing party nor Chaplin himself brought up his own brother's King, Queen, Joker of twenty years before.