2010’s “Iron Man 2.”But Johansson divulged in a new profile for Vanity Fair that when she took on the role, she “had never stepped foot in a gym” before her intense training for the action flick.The “Lost in Translation” actress also described her casting — at around age “23 or 24” — as “a humongous moment” for her.“I had never stepped foot in a gym, and I had five weeks to prepare myself for these huge stunt sequences,” she explained.“Back then when we were doing it, over a decade ago, it was before we kind of figured out how to be most efficient in the process of shooting stunt work – what could be handed off to other stunt people and what the actor would practically need to know,” she continued. “So I was doing these huge choreographed sequences and I had no previous experience with any of that stuff.