The film’s first bravura action sequence is a long fight aboard a train. As Wilde fights off Elly’s attackers, she keeps seeing Argylle in his place. That meant that every beat of the scene had to be filmed with both Cavill and Rockwell, so that Vaughn and the film editors could coherently intercut the footage. It wasn’t an easy task to pull off!

“Sam and I were watching each other and just trying to make sure that we had a similarity of movements,” Cavill tells EW in his first interview about the film. “Certain movements worked better for him, so I would mimic those, and then different movements in other places worked better for me, so he would copy those. Fight scenes are tricky and complex, especially in a cramped space like that with lots of hard edges.”

PETER MOUNTAIN/UNIVERSAL PICTURES; APPLE ORIGINAL FILMS AND MARV

Though this innovative approach meant that both Cavill and Rockwell had to work harder than if they had just been doing the scene by themselves, they also got to share the burden.

“It’s quite nice doing these things when you have someone doing the exact same work as you,” Cavill said. “So I do my bit, or Sam does his thing, and the other one gets to rest. The camera moves on, and we get to have a nice break. It was definitely a new way of doing things, but I enjoyed it. It was a good challenge.”

Although Cavill and Rockwell’s movements had to be perfectly aligned, their appearances certainly aren’t. While Wilde sports long hair and a shaggy beard, Argylle wears a green velvet suit and rocks a flat top haircut. It wasn’t Cavill’s choice, but he says he appreciated the change from his typical onscreen looks.

“That was actually Matthew’s pitch, his signature style,” Cavill says. “I wanted to have fun with it. Matthew said, ‘Look, this guy’s going to have a particular look and you’ve got to trust me.’ And I did! That’s the kind of thing I was looking for. I’m glad I did it.”

There are still more mysteries to be unraveled from Argylle. The Apple Original Film will be released in theaters worldwide, in partnership with Universal Pictures, this Feb. 2, before streaming globally on Apple TV+.