'I look at things differently now,' he told one interviewer. 'I look at the news differently. I look at the people in power differently. I've hooked up with Amnesty International and I do what I can. Lord of War is a violent movie, but it's also a profound comment on violence.'

Arms campaigners were delighted with their new celebrity recruit, and both Amnesty International Worldwide and the Control Arms campaign snapped up interviews with him for their websites. The press talked admiringly of Cage's 'Damascene conversion', crediting his wife, Alice Kim, and his two sons for his newfound maturity.

However, Cage's campaigning career has hit a snag. He is unable to become an ambassador for the anti-arms cause because he remains a fully paid-up member of the National Rifle Association of America.

The NRA is 'committed to preserving the right of all law-abiding individuals to purchase, possess and use firearms'. It was previously chaired by Cage's fellow actor Charlton Heston, who was memorably demonised by Michael Moore in his film Fahrenheit 9/11 for his provocative speeches in favour of gun ownership.

Anna Macdonald, campaigns director at Oxfam, said: 'There were some discussions about getting Nicolas Cage to support the Control Arms campaign.