Moon Knight star Oscar Isaac used his brother, actor and journalist Michael Hernandez, as a stand-in for his Moon Knight alter-egos on set.

Marvel’s Moon Knight suffers from dissociative identity disorder, taking on multiple personalities during his crime-fighting escapades. Now, Isaac has revealed how he filmed scenes in which there’s more than one of him on screen.

During an interview with The Hollywood Reporter, the 43-year-old actor explained how his brother, Michael Hernandez, stepped in to help while filming those alter-egos.

“[Michael] would play whichever character I wasn’t playing in the moment,” he explained. “So, sometimes, I’d have to arrive on set and decide which character I wanted to play first. And I’d rehearse it as that character, and then I’d play the other character and give notes to my brother.”

Although Hernandez is not seen on screen, his appearance on set gave Isaac a fellow actor to bounce off and interact with – the illusion that he was acting against himself.

“I’d figure out the blocking, the energy, all of that stuff, and make those decisions before cameras rolled, which is tough,” he added. “Usually, as an actor, the thing that you really look forward to is the unexpected. That’s how you find spontaneity. So, that was one of the big technical challenges of the show.”

Speaking separately to Vanity Fair, Isaac said “It was wild to have him on set and to play off of. He’s a great actor and we share DNA, so he was very helpful. I couldn’t have done this with anyone else […] He really knows me so well, so we improvised sometimes together. It was so much fun.”

Moon Knight’s alter egos include mercenary Marc Spector, the weirdly-British Steven Grant (who Isaac promises has a dodgy accent on purpose), as well as Mr. Knight – the white-suit-wearing police consultant who looks more like a classic gumshoe.

Some of these can be seen in the recent trailer, alongside the Egyptian god Khnoshu (voiced by none other than F. Murray Abraham).

Marvel boss Kevin Feige recently described Moon Knight as ‘brutal’ insisting that Marvel isn’t holding back from the darker subject matter. However, the Batman-like hero won’t just be a Marvel version of the Dark Knight – a comparison which is often made amongst comic book fans.

Source: Oscar Isaac Got His Brother to Play Moon Knight's Alter-Egos On Set