It's gotta be weird for Hollywood actors to see reflections of themselves in their stunt doubles. But it's even weirder when we see them together.
Hollywood uses different tricks when telling stories about twins or doppelgangers. In The Social Network, for instance, Armie Hammer's face was digitally placed on another actor. And plenty of other movies have seen dual performances from a single actor. Dr. Jekyll and Mr. Hyde was one of the earliest examples and movies like Dead Ringers and Enemy have followed suit in recent years.
This is something different.
Stunt doubles are essential, unappreciated people in the film industry. They often risk injury to get the right shot, and nobody ever knows they're in the movie! Stunt doubles are only meant to be seen from the back, or in passing. So they rarely look like the actor they're standing in for. They're just dressed alike. That makes for a startling dynamic when you catch both actor and stunt double together. This slideshow is proof.