Like writer Roth and De Niro, Damon saw the film as a fictionalised study of seemingly ordinary men and women who worked anonymously for the CIA. He met with many families of retired CIA operatives to learn first-hand how working for the super secret agency impacted their home.
'It's hard for relationships to last,' he muses. 'It is a really high pressure job. Edward lives in a world where the stakes are high, and he can't afford to trust even the people close to him.'
De Niro plays General 'Wild Bill' Donovan, inspired by the army official who created America's first intelligence service, and handpicked Edward for a career in CIA. To his co-stars the opportunity to work with De Niro as an actor itself was enough to accept the film.
Gambon, the British thespian best known in America as the wizened Hogwarts headmaster Dumbledore in the recent Harry Potter films, says: 'To all us boys who are actors, he's our god. They should get him to direct him every film, then they could get any actor they wanted.'