VIDEO: Sydney Sweeney on her role as boxer Christy Martin

SARAH FERGUSON, PRESENTER: Christy Martin was a trailblazing female boxer who revolutionised the sport in the 1990s.

The fighter from West Virginia known as 'the Coal Miner's Daughter'. She was the first female boxer signed up by legendary impresario Don King and was undefeated in the ring for a decade.

But in her personal life, she was fighting for survival, hiding her sexuality, trapped in a marriage that turned violent.

Australians director David Michod and writer Mirrah Foulkes have turned this life into a Hollywood film... with actor Sydney Sweeney playing Christy.

(Excerpt from movie) 

SARAH FERGUSON:  Sydney Sweeney and David Michod, welcome to 7.30 and I've just seen the film and honestly, I'm still stunned. Welcome.

SYDNEY SWEENEY, ACTRESS: Oh, thank you. 

DAVID MICHOD, DIRECTOR: Thanks, Sarah. 

SARAH FERGUSON:  Sydney to you first. Why did you want to play Christie Martin?

SYDNEY SWEENEY:  Well, to be honest, I didn't know who Christie was before I read the script, and I remember calling my team right afterwards and I was like, I don't care, I have to be this person. 

This is the most incredible and inspiring woman I've ever read in my entire life. And then after meeting Christie, I was like, this is, she's amazing. She is the most full of energy and life and an incredible woman I've ever met. And I was like, this story, and this woman deserves to be known by the world. She's so inspiring. 

DAVID MICHOD:  I think what's also disarming about her is that despite the fact that she was not just a fighter, but an amazingly powerful one, but given what she's been through, there's something really disarmingly sweet. 

SYDNEY SWEENEY:  She’s so sweet. She's shy too.

DAVID MICHOD:  Yeah, she carries, she still to this day she has a little Pomeranian that she carries with her everywhere, that is her emotional support, but I don’t know. I love her so much.

SARAH FERGUSON:  Sydney, I want to talk to you about the transformation that you underwent to play this role. You know that you went through a very significant physical change. How did you approach it, physically and mentally? 

SYDNEY SWEENEY:  Well, the mental and physical transformation were very different from one another because the physical side is just, just, you have to train every day. You have to be consistent, you have to make sure, I mean, I was drinking protein shakes after protein shakes, after protein shakes, having to plug my nose and just chug it. It was so gross. Weight training, morning and night boxing all day. So that's a physical and mental challenge on its own. 

And then the emotional and mental preparation to play Christie was its own battle in a sense, because it was one of those interesting things where when you get to see the person and talk to the person, you want to ask all these questions, but you have to also keep in mind that the person you're talking to now has had a vast amount of years and experience past who she was when we first meet Christie. 

So you have to discover and kind of pick apart, okay, what has carried over from 22-year-old Christie versus now and what has changed. And it is kind of like a puzzle piece of figuring out what stays and what goes and what comes back in at different parts of her life. How does she become who she is? So it's like a fun little discovery book that I got to put together.

SARAH FERGUSON:  On the boxing itself, from the first punch in the movie, which is quite shocking, that continues throughout the movie. How did you, together, work out how to make the boxing so real?

DAVID MICHOD:  I had a stunt coordinator, fight choreographer named Wally Garcia, who I just loved. 

SYDNEY SWEENEY:  He’s amazing.

DAVID MICHOD:  And was very important to me from the outset that the fighting feel, real fighting as strategic and as intricate as it is, is kind of a mess. It's a mess of exhausted clinches and swings and misses. 

And he lent into that very quickly went, okay, this isn't all just kind of matrix style ballet. It's a mess, but you have to be controlled when you're doing that. As much as I tried to control it, Sydney just wanted to hit people and get hit herself, which is great because I think if you had been afraid of. 

SYDNEY SWEENEY:  Oh, would not been able to. 

DAVID MICHOD:  It wouldn't have worked.

SARAH FERGUSON:  Dave Michod, while this is a boxing movie, it's really a movie about domestic violence and coercive control. How did you and your co-writer Mirrah Foulkes approach that subject in the creation of the script and the film?

DAVID MICHOD:  It was something about the whole, I was drawn immediately to wanting to understand how those kinds of relationships function. 

I mean, Christie is a powerful woman, but stayed married to this man 25 years her senior for 20 years. How does that function? Mira and I both did a lot of research. There's an amazing book by Evan Stark called Coercive Control. That's like the kind of bible of this stuff, but then also reading a lot of the stuff that Jess Hill in Australia has been doing.

(Excerpt from movie)

SARAH FERGUSON:  Sydney, did you understand Christy's motivations when she goes back to her husband and manager, Jim Martin?

SYDNEY SWEENEY:  Yes. For her, she wasn't going back to be with Jim. She was going back to take control of her life, and she was going back to claim what was hers.

DAVID MICHOD:  Yeah, it's tricky because a lot of that also is about, there was a line, if you remember, we cut it out. It was, you said, I'm going back because it'll be worse if I don't. 

It was a lot to unpick in that, and we cut that line out because it was actually quite confusing. But it's so true of so many women's experiences that the amount of complex work that men have to do to control a partner, there's an equal amount of complex work women have to do to just self-preserve.

And quite often they find themselves going to have to go back to the lion’s den to just stay alive. 

SARAH FERGUSON:  And finally, Sydney - how much did it matter to you that Christy Martin liked your portrayal of her?

SYDNEY SWEENEY: Honestly, that was probably the most important part for me. I always say that I did this for Christie, so her opinion was all that mattered to me.

SARAH FERGUSON:  To both of you, congratulations on the film and thank you very much indeed for joining us.

SYDNEY SWEENEY:  Thank you.

DAVID MICHOD:  Thanks Sarah.