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.”