One of our favorite parts of "The Social Network" (we have many) was the Winklevoss twins.
To get everyone up to speed, director David Fincher used movie magic to turn one actor -- the handsome Armie Hammer -- into two Winklevoss twins. When both twins had to appear in the same shot, Fincher brought in actor/model Josh Peace to be a body double. In post-production, Fincher digitally ripped off Pence's face and replaced it with Hammer's.
Of course, this isn't quite late night talk show chitchat. Instead, Jimmy Kimmel cooked up an alternate solution for Hollywood body doubling: simply ask the universe for "a double." Like that, a double will appear.
Stick with this video to the end, the final minute or so gets doubly funny.