Cillian Murphy. He only shows up whenever he has a movie to promote and I know absolutely nothing about his private life. He is a very versatile actor and has managed to establish himself quietly. Many famous actors are huge attention seekers in their twenties (looking at you Colin Farrell) but then calm down as they get older.
Good shout - excellent actor.
There is an actor called Stephen Dillane - whom I've rarely see do an interview. He plays Stannis in Game of Thrones and was Thomas Jefferson in 'John Adams'. He has also been in Welcome to Sarajevo, The Hours and a few other films.