With reporting by Josh Horowitz

It would be difficult for any hardworking actor to not pick up a few new skills from their roles. Play a spy, and maybe you learn a new real-life way to sneak around. Playing a sailor? You may soon be a good hand on the high seas in your own life.

This has certainly been the case for "American Ultra" stars Jesse Eisenberg and Kristen Stewart, who both told MTV News that they'd picked up a trick or two on-set during their careers.

Eisenberg, who described his scenes in "American Ultra" as "either Lucky Charms or muy thai," claimed that he can do one stunt from this movie -- in which he plays a sweet stoner who has no idea he's a deadly special forces sleeper agent -- and one magic trick from roles in movies such as "Now You See Me."

As for Stewart, who plays Eisenberg's girlfriend in "Ultra," her trick is a bit more scandalous.

"I can roll a really good joint," she said. "And I genuinely did learn that when I was very young on a movie set, a prop guy taught me."

See more of what Stewart and Eisenberg have to say about "American Ultra," their on-set tricks and "Batman V Superman: Dawn Of Justice" in the clip below.

"American Ultra" hits theaters August 21.