Discussing why she wanted to immerse herself in the role of Tammy Faye, Chastain explained: “Well, you know, I’d just done Zero Dark Thirty and I was on the press tour for it. And it couldn’t have been a more different character than Maya. Maya is like an eye for an eye. She’s all about revenge. And Tammy Faye is love through anything, and you forgive. And then you love without judgement, so it was like a healing balm in some sense.

“I also just… she made me laugh. And so the idea of studying her for seven years, I had so much time with her. She loved camp, she was goofy.

“And I had plenty to study. I mean, I had to learn how to sing, I had to learn a new accent. There was so much with who Tammy was that I got to explore and challenge myself with that. And in addition to all the acting challenge, the emotional challenge, I wanted to celebrate her and let me examine her relationship in terms in society.”

Chastain continued: “In terms of the Steve Peters interview, I wanted to acknowledge her for that and maybe shift the focus of the conversation away from ‘Oh, wasn’t she garish about her mascara?’ and ridiculousness of her costumes, which actually I don’t agree with.

“I think she was fabulous. And move away from that to like, what she actually did and how, what a loving, courageous human being she was.”

The Oscar-nominated actress also addressed what she considered so inspiring about the historical figure and televangelist.

“In some sense, it’s like she had no ego, which is a hard thing to understand and play,” explained Chastain.

She continued: “I’m such a sensitive person that many times I kind of just want to stay in my house. I don’t like to go to big events. I don’t like, you know… I’m quite shy. And she’s someone who I think was the same way, but she really forced herself out there.

“She’s like, ‘Yeah, I know, you’re gonna make fun of me. I know, you’re gonna laugh at me. But that’s OK. Because I’m gonna make you laugh back and I’m gonna make you love me. And we’re gonna, you know, have this connection.’ And that I think was such a beautiful thing to play and experience.”

On working alongside Spider-Man and Tick, Tick… Boom! star Andrew Garfield on the film, Chastain described the intense bond that the pair struck up playing Tammy and her husband, Jim Bakker.

“Andrew and I were very codependent on this production… which makes sense because Jim and Tammy were quite codependent with each other,” revealed Chastain.

“We went to church every Sunday to start our week, we went to actual Heritage USA, which is, you know, where it all started with Jim and Tammy. We would sit in the make-up trailer for hours, getting into our characters, watching the videos, listening to the voices talking about what we were about to do.

“I don’t know what my performance would have been without Andrew because it’s so closely related to what he did. And yes, it was an incredible work experience because he is as obsessed with the work as I am and it’s wonderful… when there’s that, you know, synchronicity.”

Photo Courtesy of Searchlight Pictures.

There has been much commentary and strong reactions to the stark physical transformation that Chastain underwent through make-up and prosthetics to play Tammy Faye.

Debate has also emerged on social media and among critics about whether actors should physically transform so extensively through make-up and prosthetics to become a character, or whether performers more closely resembling the character should get the role.

When asked for her thoughts on this, Chastain noted that such a stance is “interesting” but thinks “the sad thing is by making it we devalue the incredible artistry of the hair, make-up and prosthetics team”.

She added: “It’s beautiful what they do and to say like, ‘Oh, you should be performing without that’, it’s like saying, ‘OK, well then we should be performing without a costume designer’, right? Like, I should just bring my own clothes? Like, why not allow people to help create the look of a character?”

Photo by Daniel C. McFadden. Courtesy of Searchlight Pictures.

In the instance of The Eyes of Tammy Faye, Chastain noted: “Also, when playing someone like Tammy, I mean, she was four foot 11 – tiny! She was this tiny little like squeak of a girl when she was in college, where we start, and where we end – because we’re [seeing] so much of her life – is so incredibly different. So she has so many shapes throughout her life and throughout our film, how do you cast one person, that looks like all…? It’s impossible because she changed so much.”

Noting that an alternative would be to film over longer spells of time and to literally change your body type, Chastain expressed that this is not the “reality of how we work” and “undervalues the artistry of the hair and make-up team and the brilliance of what they do”.

And what a job they have done too.

The Eyes of Tammy Faye is out in UK cinemas today. Find something to watch tonight with our TV Guide.

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