Homeland star Damian Lewis has spoken of his amazement at being awarded an OBE by the Duke of Cambridge, describing the honour as a huge surprise.

Lewis is one of Britain's biggest acting exports and has become an international celebrity on the back of two roles - both playing US servicemen.

His performance as Major Richard Winters in the 2001 Second World War epic Band Of Brothers made his name and more recently Homeland, in which he played returning prisoner of war Marine Sergeant Nicholas Brody, confirmed his star status.

Speaking after the Buckingham Palace investiture ceremony, Lewis said about being nominated for the OBE: "I was stupified, I had no idea, so it was a big big surprise." The actor, who was joined at the Palace by his actress wife Helen McCrory, added: "I remember when I heard I was being awarded it, it was a little bit like 'now you've got to prove it'," he added laughing "it was a bit like being asked to be a prefect, now I have to be extremely responsible."

William revealed he and Kate are avid watchers of Homeland the popular drama about Lewis' character, a US marine rescued after being held captive in Iraq, and CIA officer Carrie Mathison, played by Claire Danes, who believes he has been turned by al Qaida.

Speaking about his brief chat with the Duke the actor said: "He said 'Catherine and I are huge Homeland fans'.

"He said 'you appeared again the other night briefly, and we all got very excited,' which is true but it was also on Sunday night which means he is absolutely up to date with the latest episode and I'm amazed they have time for that."

The US drama has won five Golden Globe awards since it first aired in 2011 and describing its appeal Lewis said: "I think people watch Homeland for different reasons. There's a compelling thriller at the centre of it, but I think people also got very engaged in the relationship at the centre of it between the CIA officer and this turned soldier.

"And how damaged they both were made their relationship compelling, (they were) co-dependent and needy and un-trusting at times and romantic and explosive at other times.

"Set against a backdrop of a plot to blow up the United States it was heady stuff."

The Duke hosted the investiture and not the Prince of Wales, as had been previously announced. The event was always a long standing commitment in William's diary.