The Mamma Mia! star takes on twice the work in the film, starring as Latif Yahia, an Iraqi man who was forced to work as a body double for Hussein's eldest son Uday, also portrayed by Cooper.
The Brit felt compelled to tackle the "incredible" script - and reveals several stars and moviemakers had refused to take on the project.
He tells FOX411's Pop Tarts column, "The story itself is incredible, I think a lot of actors and directors were tentatively scared of it when the script was first developed a few years ago, I know a lot of people decided not to take it on but I didn't fear that... I tried not to think about that too much, even now.
"It was real, this really happened to a man (Yahia) and he was emotionally and physically scarred from that."
The Mamma Mia! star takes on twice the work in the film, starring as Latif Yahia, an Iraqi man who was forced to work as a body double for Saddam Hussein's eldest son Uday, also portrayed by Cooper.
The actor learned how to fight for the role - and Cooper admits the sport is much harder than he expected.
He tells Britain's OK! TV, "I did some boxing training - I was awful at it. I respect boxers so much.
"Boxing is unbelievably difficult - (after) two minutes I was exhausted and on the floor! I trained to make it look like I knew what I was doing but I'm sure if a professional boxer watched it they would think it was pathetic."
The British star insists he is grateful for the success of the hit film, but admits he has struggled to find more challenging roles since appearing as the all-singing, all-dancing Sky alongside Amanda Seyfried, Meryl Streep and Pierce Brosnan.
So he immediately snapped up The Devil's Double, based on the book of the same name by Latif Yahia, an Iraqi man who was forced to act as the body double of troubled Uday Hussein.
Cooper, who portrays both Yahia and Hussein in the film, tells WENN, "I'd love people to see this because it was so rewarding and I worked so hard on this and it's a low budget film. It's nice to be seen in a different light I suppose...
"Up until now, in terms of my film work, I've enjoyed doing supporting roles but it's quite problematic trying to sell yourself to get into any film you possibly can, but then you can be pigeon-holed. Being so fortunate that you end up in a musical film (Mamma Mia) that does extremely well, the opposite end of that is people think you're all-singing, dancing and that's what you do; you're a musical theatre person. I'm really thankful to have the opportunity to be able to show a different side of what I can do."
The Mamma Mia! star takes on twice the work in The Devil's Double, starring as Latif Yahia, an Iraqi man who was forced to act as the body double of troubled Uday Hussein, also portrayed by Cooper.
But the British actor admits he took his method acting a little too far, and it was up to his brother to help him snap back to reality.
He tells WENN, "(I kept thinking), 'How can I play this hideous man?' There was something I had to truly understand about the mentality of the man to allow me to actually portray him because there's always an aspect of yourself (in the role) so I had to find something humane within him.
"I couldn't do that. I just found him despisable (sic) until I looked into the root of this insane monster and the relationship with his father, who was a dictator, and the awful relationship and the things he was exposed to as a young man; the scenes of torture and the damage that was created was my key in...
"It did change me because I was so absorbed and looking through his eyes constantly. There were moments in my behaviour, I'm sure, where I was becoming slightly more erratic and demanding. If I'd be in a restaurant I'd sense it and just have to monitor it all the time. The rest of the cast would say, 'Dom, you're being a bit Uday...' My brother was on set with me, which was a great leveller. He wouldn't allow me to behave in any other way."
And Cooper reveals the fake teeth he had to wear to play Hussein helped him get straight into character.
He adds: "Once I was on set I was very aware of who I was playing because they (Hussein and Yahia) were so unbelievably different. I understood the difference between their physical gestures and I had these fantastic prosthetic teeth which immediately changed the physical sensation I had. The moment I had those teeth in my mouth I felt the manic, depraved monster and when they came out I felt this warm, solid generous human."
The Devil's Double is based on Yahia's own book of the same name, which details his experience as Hussein's decoy.
Uday Hussein was killed in 2003 during a raid by U.S. forces on a home in the Iraqi city of Mosul.
Lionsgate has released the trailer and poster for its upcoming film The Devil's Double and, well, it looks pretty bad-ass. Directed by Lee Tamahori, the flick stars Dominic Cooper, Ludivine Sagnier and Raad Rawl, and tells the story of working as the body double for Saddam Hussein's son, Uday Hussein. Check out the trailer and poster below, right after the official synopsis. It hits theaters on July 29.
Based on a gripping, unbelievable true story of money, power and opulent decadence, Lionsgate’s THE DEVIL’S DOUBLE takes a white-knuckle ride deep into the lawless playground of excess and violence known as Bagdad, 1987. Summoned from the frontline to Saddam Hussein’s palace, Iraqi army lieutenant Latif Yahia (Dominic Cooper) is thrust into the highest echelons of the “royal family” when he’s ordered to become the ‘fiday’ – or body double – to Saddam’s son, the notorious “Black Prince” Uday Hussein (also Dominic Cooper), a reckless, sadistic party-boy with a rabid hunger for sex and brutality. With his and his family’s lives at stake, Latif must surrender his former self forever as he learns to walk, talk and act like Uday. But nothing could have prepared him for the horror of the Black Prince’s psychotic, drug-addled life of fast cars, easy women and impulsive violence. With one wrong move costing him his life, Latif forges an intimate bond with Sarrab (Ludivine Sangier), Uday’s seductive mistress who’s haunted by her own secrets. But as war looms with Kuwait and Uday’s depraved gangster regime threatens to destroy them all, Latif realizes that escape from the devil’s den will only come at the highest possible cost.
Dominic Cooper plays the former Iraqi leader's son Uday and his stand-in, Latif Yahia, in The Devil's Double, which details true-life events in the country prior to Hussein's downfall in 2003.
But Cooper has revealed film bosses decided to leave the more brutal accounts of stomach-churning violence and torture out of the script - because the reality of the hellish regime would sicken cinema-goers.
He tells British TV show This Morning, "It's a terribly tough film because (of) some of the images, (but) the truth is, they have been dumbed down. The true horror of the events that took place amongst that regime are truly shocking. It's just about obeying that regime - don't talk against it, don't stand against it and you will be okay. It was very much that system."
In 2010, Dominic Cooper made a big splash opposite Carey Mulligan in the Oscar-nominated An Education. The role showed off his suave, dapper side, but in his latest film, the Sundance debut The Devil's Double, Cooper really sinks his teeth into a role (or in this case, roles) and pushes himself to the extreme.
The Devil's Double tells the story of Latif Yahia, an Iraqi military officer recruited to become the fiday, or body double, of Saddam Hussein’s tyrannical son Uday. Cooper plays two distinct roles in the film: the conflicted Latif, who struggles to take on his new job, and the murderous party animal Uday. The film is insane, to put it lightly, and the crazed tone is in part to Cooper's disappearance into the two men's stranger-than-fiction world.
The Devil's Double is a wild ride and a real departure from previous work? How did you get involved with the film?
I read it, with the understanding that someone else had the part that it might fall through. I read it knowing that it had been around for many, many years, many directors had been attached, It was a script that stuck in my head. I was fascinated by how little I knew of something that affected so much of my life and the world, and ultimately, it was this mad gangster movie and the opportunity for an actor to play both those roles.
I was unsure about the person I heard doing the part at the time, it didn’t make sense to me. I managed to get into a room with Lee [Tamahori, director] and I auditioned for hours with him. I brought into the room something I thought this person was and who the other person was, and next thing I knew...I was doing it. It was the most exciting moment in the work I’ve done so far.
Were there resources to help you better understand how this world operated? To give insight into living out both Latif and Uday's lives?
No, there was nothing to like that. The difficulty for me was to understand and have compassion for this person, which I think you have to do when you’re playing someone. When you’re inhabiting someone, looking through their eyes and understanding their complexities.
With this guy, I couldn’t. I couldn’t understand him - he was a madman, a berserk man that needed help. Everything he did was disgusting and atrocious. It wasn’t necessarily about him, they became more fictional characters. I think that was important for me and Lee both to kind and reach a point and use this as an incredible story but we don’t know what they said we don’t know the relationship they had. We’re making a film. And this is not meant to be stooped in the real truth. Lee said the only truth in this film is that the US got him. That's the one fact that we know of this story.
That's evident in the film. You're constantly wondering what's real because the tone jumps from gritty realism to over-the-top, often comedic levels. Uday is executing these insane operations and one minute you're laughing, the next, you're horrified. How did you balance the tones of the film?
That’s why you need to be in the hands of a genius like Lee, with this kind of material. An actor doesn’t know that. That’s why I have to rely on him for the tone and sensibility of the piece. I don’t know what he’s going for. I can kind of get a vague understanding. I didn’t know he was making a outrageous, horrific gangster film. What I knew is that he made the most stunning debut film with Once Were Warriors, and I knew that, if any one can handle that kind of material and those people, and can understand how those gangsters type tribal people. then he is the person to do it. And my job is to come up with something that fitted with that environment. And although sometimes humorous because you're so baffled and amazed that this human exists.
Were there moments where you wanted to pull back but Lee pushed you to go further?
I think it was a matter of bringing it down. He kept me very still, that was very helpful. It was his actual energy on set that was so inspiring. It was a short shoot, relatively cheap, and we had a lot to do. Technically it was difficult because of the doubling up of the scenes.
What was the process of shooting two roles in one scene? Were you constantly repeating the setups and blocking?
Yes, and that was why you only really got three takes on anything. Some people like to go on and do take after take, I couldn’t do that. There wasn’t time. It wasn’t stressful, I loved it. And you watched him and he had to create a new environment. It would be like...Lee wasn’t allowed to use this position or camera angle. And he was completely reconfiguring his ideas and I always think that creates the most creative inspired work and its constantly moving. Watching him with the amount of decisions he had to make, [laughs] I kind of felt my job is kind of easy.
What challenges did you face embodying two separate roles, bouncing between characters on a whim?
I needed to make one who is watching it believe it is two different people no matter how much reconstructive surgery one of them had had and how much they needed to look the same which they did, it was difficult to decide who was who. I needed them to be clearly two different people, I got help from my wonderful dialect coach, I got help with the make-up lady. It was about making a vocal difference and physical difference and the way in which the two characters thought differently.
Into the film, you slowly realize there's a third character you're playing. Was that intentional?
Oh, definitely. The one that Latif had to transform into. I wanted here to be an intricate difference in the way he went to perform as Uday. I wanted him to be slightly different still. Not quite succeeding whole heartily in becoming him - there was still something holding him back. That’s why when you see him practicing in the mirror there’s still this tentativeness about him. He was not a showman, not an actor. There was no reason he should have been able to manipulate who he is. He did it to the best of his ability and I needed that to be clear.
What's next for you? Anything in the can?
My Week With Marilyn with Kenneth Branagh. And Captain America.
That must have been a bit bigger than what you were accustom to.
It was massive - and intriguing.
You play Howard Stark in the film, a character with a wealth of comic mythology. What does your role in the actual film entail?
He moves the story along. He transforms him into Captain America. He’s Iron Man’s dad! He was a playboy, it was fun. How much he winds up in the film, who knows. But I hope he has an affect on it.
The Mamma Mia! star took on the challenging role of the Iraqi dictator's son Uday in the film, as well as playing Latif Yahia - the man forced to act as Hussein's body double.
Yahia, who wrote the book the film is based on, was recruited to pretend to be Hussein from the age of 12, and was even made to undergo painful cosmetic procedures to enhance the likeness between the pair.
Cooper insists the roles have been his toughest to date - because he struggled to grasp how the two men could have grown up to be so different.
He tells the BBC, "It's quite a horrible part. It was a difficult challenge, trying to understand who this guy (Hussein) was and why he did such unbelievably terrible things, and then to play this innocent guy (Yahia), who he forced at gunpoint to be his body double."