Christy director David Michôd has said that the dedication of the film's leading star Sydney Sweeney was like "gold dust", while screenwriter Mirrah Foulkes said it had a "huge impact" on set.
In the upcoming sports drama, which is due to be released in cinemas in Ireland on 28 November, the Hollywood star plays famed American boxer Christy Martin, who is credited with putting female boxing on the map in the mid-nineties.
Australian filmmaker Michôd, known for The King and Animal Kingdom, directed the project from a script he co-wrote alongside Foulkes, his partner of 20 years.
The couple worked together for the first time of the biopic which charts Martin's struggles inside and outside of the ring as her relationship with her trainer turned manager-husband Jim Martin (Ben Foster) becomes increasingly controlling and abusive.
Speaking to RTÉ Entertainment over Zoom, the director and screenwriter spoke about the anxiety-inducing process of bringing this shocking true story to the big screen, with the blessing of Martin herself, who was heavily involved in the making of the film.
Foulkes said: "We started by building up a relationship with [Christy], getting to know her, getting her to trust us, and then we just talked a lot - a lot about her life and we tried to interrogate every tiny facet of it, to figure out what part of it we wanted to tell."
Martin was understandably reticent about having her life story adapted into a film, something Michôd admitted was "really nerve-wracking".
He said: "I think I went into it kind of naively, I got excited about the idea of the movie. Quite early in the process [I realised], 'Hang on a minute, there's a real person here, they're having to surrender control of the representation of their life to us, and that's an unbelievable responsibility'.
"There were many steps throughout the process where we were just anxiety-stricken. Obviously, the big one was showing her the movie for the first time. We love her so much. She called us immediately after watching the movie."
"We've never been so relieved in our lives," Foulkes continued. "It sinks in over time, the responsibility of taking that on, and especially when you like that person very much."
Sweeney had months of prep and gruelling training to transform into the boxing great, and Michôd said her dedication shone through during production.
"Sydney's commitment was clear to everyone that she was doing the work, doing the training, doing all the nutritional stuf... That was all clear to everyone pretty quickly," he said.
"Her commitment to work in general - I just loved [it]. Every day Sydney was on time, turned up to work with a big smile on her face, wasn't disappearing back to her trailer and she was there to work, did it with a smile on her face all day and then left at the end of the day with a smile on her face. For a director that is just gold dust."
"It has a huge impact, that stuff," Foulkes agreed. "When you're carrying the film, in every single scene of the film and you've got that kind of enthusiasm and energy, it makes it really hard for anyone on set to feel sorry for themselves. It trickles down from the top and everyone just kind of rallies a little bit."
Her co-star Ben Foster's chilling transformation as Jim Martin is unsettling to watch, and he thoroughly disappears into the role.
Michôd said Christy Martin "didn't want to go anywhere near him" on set.
"She was really freaked out," Foulkes said. "It is a compliment for an actor, but she really struggled to be in the same room as Ben when he was a character."
Michôd added: "What brought me to tears at the end of the shoot, when we wrapped Ben at the end of the movie, Christy had subtly from a distance clocked that, 'Oh, he's not the monster'.
"Their embrace, at the end of the movie, I just lost it. I was always waiting at the end of the movie, waiting for that thing that makes me burst into tears. And that was the moment."
Christy is out in cinemas on 28 November.
