Oscar Isaac sports a British accent in Marvel’s upcoming series “Moon Knight,” but it turns out not everyone at Marvel Studios was wholly on board with it during production. Isaac stars in “Moon Knight” as Marc Spector, a former CIA operative turned mercenary who becomes the conduit of the Egyptian moon god Khonshu. Marc has dissociative identity disorder which manifests in four distinct personalities, one of which is a quiet and long-suffering British man named Stephen Grant.

“It wasn’t necessarily written that way at all,” Isaac recently told Radio Times about his character’s British personality. “And so I thought, ‘OK, well, let me see what [Marvel Studios president] Kevin [Feige] says about this.’ And so I had a meeting with Kevin, I said, ‘This is how I’d want to do it.’ And he said, ‘Yeah, OK, go for it.’”

“It’s funny, because afterwards he told me they didn’t know what the hell I was doing,” Isaac added. “And they weren’t sure it was going to work at all. But you know, in the end I’m glad we did that, because everyone says it kind of makes the show.”

Isaac has already touted “Moon Knight” as Marvel’s “first legitimate character study” since “Iron Man.” The superhero Moon Knight is a Batman-esque vigilante. For Isaac, it was the character’s dissociative identity disorder that provided a window into making the series feel far different than the usual Marvel fare.

“What I love most about this thing is that it’s an exploration of a mind that doesn’t know itself,” Isaac told Empire magazine earlier this year. “A human being that doesn’t know his own brain. I found that really moving: what the mind is capable of as far as survival. But the workload was massive: the technical challenge of embodying these different characters, physically, the way I manifest my body… It required a lot of energy.”

“Moon Knight” debuts March 30 on Disney Plus.