Nigel Derek Harman (born 11 August 1973) is a British actor, most famous for his role as Dennis Rickman in the BBC soap opera EastEnders. He has worked mostly in theatre, with the stage being described as his "first love". He starred in the final series of Hotel Babylon. In early 2013 he started filming for the fourth series of Downton Abbey, and is currently playing the role of a visiting valet Mr Green.