Without the casting crews knowledge, one of the prophets (George Gilbert) was actually related to his in-film descendant (played by Hogan Gilbert). The connection was only made on set when Hogan saw a photo of who his "ancestor" was cast as and realized it looked like his actual grandfather.
The song, "Baba O'Riley" (by The Who) was actually written as a tribute to Terry Riley, the legendary American minimalist composer who scored HOCHELAGA. Director Francois Girard was a long-time fan of Riley, but had never met him. Music Supervisor for the film, Robert Thompson, worked with Riley, and introduced the two of them at brunch in Brooklyn.
It was announced, on 25 September 2017, as Canada's candidate for Foreign language Oscar.
The film's premiere was at TIFF in Toronto in September 2017.