"We actively searched for something like this and then we developed it for five-and-a-half years, and I think you can't develop this for that long and not know that this story is really being forwarded by the action. I always knew that that's what it was going to be," Theron tells The Hollywood Reporter.

Adds Leitch, "You need those actors to want to do it, otherwise you won't get those genuine characters on the screen. The thing that [former stuntman and John Wick 2 director] Chad [Stahelski] and I have found with the stuff we've been doing in our directorial careers is getting the actors trained up and keeping them in the action as much as possible."

And if Theron was able to do all of her own stunts she would have. "Charlize did 98 percent of her own action including fighting, running and those kinds of things. When it comes where she has to fall down stairs or swing from a height — that she can't do insurance-wise," says Hargrave.

Theron sought out the project as a potential vehicle for her to star in her own action-packed franchise, so if there's a follow-up, she's sure to be doing some more heavy lifting.

Says the film's scribe Kurt Johnstad, "I'm prepared for a sequel. Charlize was really looking for a character-driven action movie and I told her, 'I'm going to write this script like your character is a guy, and every guy is going to wish they were your character. I'm going to create your Bourne franchise.' I see it as three movies. It might be more."

On what that franchise will look like, Theron says it's currently being discussed: "That's going to take a while to figure out. We're starting that conversation right now. We're definitely talking."

Atomic Blonde hits theaters July 28.