Leonardo DiCaprio struggled to portray J. Edgar Hoover in his elder years for a new biopic, because the prosthetic make-up made him feel "incredibly claustrophobic".
The Titanic star plays the former director of Federal Bureau of Investigation (FBI) in Clint Eastwood's J. Edgar, and spent hours every day undergoing a facial transformation for the role.
But DiCaprio was not a fan of the prosthetics, and found the shoot extremely challenging.
He tells Britain's Total Film magazine, "I found it to be incredibly claustrophobic at times, because you have so many different layers of prosthetic make-up on you, but I also had an incredible amount of weight that was put on me.
"Plus, it wasn't just the physicality of it; it was inhabiting somebody that had 50 years of experience on people around him. You have to almost slow your heart rate down for that."
Co-star Armie Hammer adds, "It was such a long process. You would have days where we'd show up at nine in the morning and be done with make-up by about five in the afternoon, and then start acting until about midnight, then spend two or three hours getting the make-up off."