So, has any film or show ever been made, where an actor was uncredited in order to hide their face from the viewers?
Yes, the TV series Charlie's Angels
John Forsythe (as Charlie) was readily identifiable by his voice but was never credited or seen.
During the show's five-year run, the identity of Charlie was one of TV's most closely guarded secrets. ...
You will get surprised to know that the world’s first porn film was made in 1896 during the silent era of films. It was a seven-minute French film that featured a woman stripteasing in the bathroom, gets bathed, and then gets dressed again. The name of the movie was “Le Coucher de la Mariée.”
The original film has been ...
There's a scene in Under the Skin (2013), starring Scarlett Johansson, where there's a baby/toddler alone on a beach - the baby is crying and looks really properly distressed and too young to be acting - I've always wondered what they did to it.
It's mentioned in an interview with the director, Jonathan Glazer. Basically, they found a baby that would cry ...
Is it common practice to award the deceased author of a character an executive producer credit on the character's TV Show or Movie?
But that's not exactly what is happening here.
The "Tom Clancy" referenced is not the "person" Tom Clancy but rather his estate without whom the series could not be made. They just reference Tom Clancy as "...