With reporting by Josh Horowitz
When you star in a movie alongside someone, chances are you get to know them pretty well. There's a lot of hurry up and wait, long stalls waiting for lighting, whatever else it is that happens on movie sets -- it all sounds very complicated and like there's a lot of standing around staring at each other.
For example, who's more likely to break into song? "Me, hands down," said Hoult. Stewart concurred.
As it turns out, the duo know each other pretty well.
Find out more about the co-stars, including who's more likely to goof a stunt, mess up a take and more.