Wissenswertes

Bud Spencer initially asked the producers if he could be credited under his real name (Carlo Pedersoli), due to the film's more serious tone compared to the titles he was most commonly associated with. He reconsidered after being told that his presence would boost the film's box office prospects.

The plot is loosely based on a real life story, which also inspired Jorge Luis Borges' tale "La Viuda Ching, Pirata". The Italian translation of Borges' tale closes with the exact words used for the title of the movie, "cantando dietro i paraventi" (singing behind the screens).