The new "Fall Guy" movie reminds me of a short story I read within the last three years or so, probably online, about a stunt double who confronts the actor he has been working with, in the actor's trailer.
The stunt double reveals that he looks even more similar to the actor than anyone had supposed - the double had deliberately changed his appearance to look different enough to not be eerily identical.
The double is actually an alternate universe version of the actor. He had been satisfied with living as a stunt double/stand-in, but he had recently found out that the actor was mistreating his girlfriend, who was the analog of the stunt double's wife from the double's original universe.
The stunt doctor kills the actor, takes his place (altering the actor's appearance enough that it appears that the "stunt double" had tried to kill the actor and had been killed in self defense), and reconciles with the girlfriend of the actor (I believe an illegitimate child was involved in the situation which probably dates the time period the story takes place in to the 20th century).
I don't remember how the stunt double wound up in the wrong universe - I think it was a rare but natural occurrence
