Two of the members of "The Avengers" team are the Hulk, played by Mark Ruffalo, and Black Widow, played by Scarlett Johansson.
The action genre is new for Ruffalo, but this actor likes trying things out of the box.
"I definitely like the idea of changing it up every couple of years, always being one step ahead of being pigeon holed has been my motto," Ruffalo said.
Johansson also took it as an opportunity to challenge herself.
"I think a couple of years ago I really had this kind of profound thought that I want to do things that are hard in some way because they are fun and engaging," she said.
"As I got older, I realized it was more fun for me to be terrified of something," she added. "It was way more fun to be terrified of something than to look at something, and go, 'Yeah, I can do that.'"
All the actors get to try plenty of new things in this film.
Johansson's best friend told her she was "exhausted" after watching the movie!
"She was on this incredible ride so I think it really does appeal, seems to appeal, to a lot of a wide variety," Johansson said.
Ruffalo said his mother told him "The Avengers" is the best movie he's ever been in.
"The Avengers" is rated PG-13.