"Preacher" is one of the most celebrated comic book series of the modern era. The Vertigo series created by Garth Ennis and Steve Dillon follows small town Texas preacher Jesse Custer after he merges with a bizarre spiritual force, granting him a supernatural power know as "the word" and shattering his faith. He sets out with his dangerous ex-girlfriend Tulip and vampire best friend Cassidy to find God -- and himself.

After years of fits and starts, "Preacher" is finally being adapted for live-action in a new AMC television series shepherded by Executive Producers Seth Rogen and Evan Goldberg and showrunner Sam Catlin. Filling Jesse's impossibly large boots is Dominic Cooper, best known as Howard Stark from "Captain America: The First Avenger" and "Agent Carter." And, as Cooper told CBR, he was "beyond terrified" about being able to do justice to the role.

WATCH: Moody "Preacher" Teaser Warns "Something Got Loose"

Ahead of the series premiere on May 22, Cooper sat down with CBR TV's Jonah Weiland at WonderCon in Los Angeles to discuss his excitement -- and fear -- over playing the eponymous role, finding what aspects of himself he needed to tap into, and who he was most afraid of letting down in the process. He also talks about co-creator Garth Ennis' involvement and feedback on the series and what playing the titular preacher has taught him about himself.

On the shocking nature of his character when he read the pilot script:

Dominic Cooper: I read it and was desperate to be part of it and then I had the thought process of, "I can't possibly do that. What even makes me think for a moment that I could do that?" And then I said I must go meet [the producers] and see what they say about it. It was very exciting for when they threw out their ideas for where they saw the show going. Because I thought how on earth can you take this incredibly in-depth, wonderful comic -- it's so elaborate, so beautifully illustrated, and I've never seen characters like it. Exactly as you said, I was desperate to do it, I thought, "Great, I must do this," and then I was beyond terrified at the prospect of being able to accomplish it and do the character justice for the people who have read the comics growing up. What I came to realize more and more the more I read the comics in my adult life is you turn the comics into films in your head. They're so filmic anyway the way they're composed and drawn out that you owe them more than just this idea that we have that we want to show them. They're already very specific in their mind of what this is and it needs to be appealing to people who have no idea what it is whatsoever.

On discovering what qualities he needed to bring to his performance as Jesse Custer:

He's probably one of the hardest characters I've ever approached to play I think because he's so far removed, he's from such a different world than the one in which I grew up. But even in terms of the area and the landscape and the world of small town Texas, but they have been so helpful and having someone with that much clarity of who they see this character as being, I get a lot of detail from the comics themselves. I have to bring a lot of what I can to this character and we had loads of rehearsal time and it was trial and error.

The thing that I discovered, in the last few days, is from the moment we shot the pilot, he changes dramatically in terms of what happens to him at the end of the pilot. It turns a character who I often felt always worried that it was becoming too morbid and heavy and depressed because of the place at which he's in at the beginning -- and that's quite hard because he's surrounded by so many elaborate, colorful and very funny characters. I think it's just finding the balance of that and also believing in the possibility of where he can go. It's a big and very long journey so just giving enough at the beginning -- and it's all discovery at the moment. I think we're all finding out really what this show, in terms of how funny it is, how dark we want it to be -- it's the same with our characters. We're just finding our way with them but it's a really exciting process.

On whether he read the comics in preparation for the role or wants to be surprised by the show's story:

I read them before I started, a few times actually, and I understand the people who don't want to see what happens because they don't want it to inform what they're doing presently. A lot of what informs Jesse and Tulip is what happened in their past which is what you get in detail throughout the comics. For me, the more information the better. The more I can discover about a person and enrich it with life and any information, even if it happens later on in their life, the way in which they react to that at that particular time still helps you understand that person before that experience has happened. Anything I can get a hold of it helps me. I've read them over and over again to get more and more -- again, because I was terrified. I felt a big responsibility to get this right. He's a very different person from myself.

On worrying about how Garth Ennis and Steve Dillon will react to his performance:

I wasn't [worried about that] because I was so petrified about going into a rehearsal room with the guys who had entrusted this role with me and hadn't really seen -- they'd seen other work I'd done -- but they've not seen me be the Texan preacher, be Jesse. I think in that moment of rehearsals heading to the Sony lot, I don't think I've ever been -- or maybe when I first started doing a play or something, I don't remember being that fearful -- but I remember thinking, "I could be doing this now and imagine if their faces all just dropped and were like, 'We have made the biggest mistake in the world casting this guy and we are screwed now.'" [Laughter] And I'd have to go, "Listen, I understand, there's a way I can get out of it. It's fine. Everything'll be fine, let me just walk away. It's all going to be okay."

So the relief after that when we all worked together and it was all starting to work and we were all finding who he was and who he needs to be at that point, it was a great relief. It kind of stopped me festering on the idea of festering about when Garth saw it. And he loved it, and he is the kindest, most gracious man. And for a man who has that shit going on in his head, I mean, he's a true gentleman.