Quantico alum Priyanka Chopra Jonas says she wanted to star in the Prime Video action-thriller, Citadel, because its story spans three separate shows that interconnect and feature casts who speak English, Indian and Italian.

"To see the success of subtitles work in English-language territories is kind of like a social experiment," she said.

"If the flagship show is in the English language and you have an Indian show and an Italian show, and the characters and the storylines blend into each other and intersect, will that take a territory of people and have them watch another language?"

Created by David Weil (Hunters) and produced by Anthony and Joseph Russo (The Avengers), the six-episode, English-language Citadel show premieres on the streaming service Friday.

Chopra Jonas and Richard Madden (Game of Thrones) play Nadia Sinh and Mason Kane, former Citadel agents who, after having their memories wiped, are living under new identities and unaware of their pasts.

That is until their former Citadel colleague, Bernard Orlick (Stanley Tucci), enlists their help to take down Manticore. Lesley Manville and Ashleigh Cummings co-star.

"They make us better. Every day on set, they push us to be better storytellers to ensure that there is as much realism in these characters and as much scope and scale in both the action storytelling and the emotional storytelling," Weil said.

"Joe and Anthony, as producers, create this energy on set that is just fully collaborative," he added. "We all get together, we read through scripts, we talk about ideas. It's like a theater troupe, almost. It's a very, very special way to work."

Despite all of her professional experience, Chopra Jonas was anxious going into the high-profile project.

"All of these guys have insane filmographies. You walk in with nerves about what to expect. What I didn't expect completely was the collaborative nature," she said.

"If we had suggestions, changes, they would be done immediately. It was always about putting the show first and everyone came in without that intention."

"Mason is a very complicated guy. The joy of this has been playing these two very different characters, but both in the same body," Madden said.

"They are the same man in lots of different ways, but each version of them, we pull out different aspects of humanity," he added. "One of them carries a lot of scars from the past and a lot of trauma and the other one doesn't."

It was fascinating for Madden to explore a character who came with that kind of baggage.

"How much of your character traits are built into you? How much is inherited through trauma and experience?" Madden said were questions he considered while building the character.

Chopra Jonas also liked the multi-faceted nature of Nadia.

"Nadia has to navigate really thick waters. She has to hold her head up high while her character is changing, her life is changing all around her, but she has to stay centered because of the burdens that she carries," she said. "That makes her very juicy."

She and Madden leaned on each other because, even to them, the series could get confusing if they didn't pay attention.

"This was a really ambitious show and I think if we didn't have each other, understanding what the other needed, this would have been hard to do," Chopra Jonas said.

Madden agreed that he and his co-star kept each other in check.

"Sometimes you're like: 'What character am I now? What do I know? What do I not know?'" he said.

"The show is completely non-linear, so you are kind of going back and forth and you have to remind each other of the story. It was like a big jigsaw puzzle."

Chopra Jonas warned viewers that every character in the show has a duality.

"Don't believe what you see," she said. "Everything is just conceptually crazy."

The action scenes were as thrilling to perform as they are to watch, the stars said.

"I have a scar on my forehead that is courtesy of Citadel. I don't even cover it anymore," Chopra Jonas said.

"The stunts were amazing. Joe and Anthony brought the most incredible stunt team on the show, obviously, with their repertoire, they have worked with the best in the business," she added.

"Nadia's character is a badass and she comes from a place of trusting her body and her instincts and I got to explore a lot of that with the stunts."

Madden thinks the show perfectly blends action and drama.

"Oftentimes, we see shows that are 80% drama, 20% action or vice versa and this show aimed to be 100% of both. I think that's what we managed to pull off," the actor said.

"For me, that's what was so exciting about these huge action pieces - they were infused with heart and drama and storytelling."