Damian Lewis has spoken about the preparation he undertook for season three of Homeland. 

The series sees his character Nicholas Brody deal with drug addiction while being held captive.

Lewis told Entertainment Weekly about the research he did into addiction before filming the series.

He explained: "I saw this extraordinary video on YouTube where a guy charts his withdrawal at different intervals... as he goes cold turkey.

"But I found it more interesting to speak to a friend of mine who's an ex-heroin addict who deals with people with addiction, and he put me in touch with ex-addicts - or, I suppose, addicts - who are now working with people. 

"I had a fascinating hour with a guy working in a Charlotte, North Carolina addiction unit at a hospital there.

"Fairly conventional modes of research, talking to people, getting anecdotal evidence, watching video and trying to reproduce that.

"[It was] fascinating, interesting and exhausting."

Lewis added: "I feel added responsibility when portraying real-life conditions because there're people out there living with these conditions and you owe it to them to represent it honestly.

"There's the added burden of trying to get it right and not letting a community of people down who suffer from this addiction. You want to represent them faithfully."

The next episode of season three of Homeland airs on RTÉ Two at 9pm on Tuesday December 3.