One day in the 90s, Jared Harris walked into a room in New York to audition for Danny DeVito. He was in his thirties then, making a living as a hard-working chameleon: a dastardly British lieutenant in The Last of the Mohicans , Tom Cruise’s alcoholic Irish brother in Far and Away , a Russian taxi driver in Happiness , Andy Warhol in I Shot Andy Warhol ..

. Always good, never the same. “He goes, ‘I had no idea who was going to walk in this room!’” Harris recalls, imitating DeVito’s rasping New Jersey bark.

(He’s an exuberant mimic and storyteller as well as a sharp observer of Hollywood’s foibles — a chat-show raconteur of the old school. He would have slayed on Parkinson .) “‘You’re so different in everything! I didn’t even know what you were going to sound like! Good luck kid, you’re gonna need it.

’ I said, ‘What are you talking about?’ He said, ‘Really? I gotta explain this to you? A successful actor is a recognisable actor and you’re trying to start from scratch every single time’.” Harris seals the anecdote with a hoisted eyebrow. He didn’t get the part.

His fortunes changed dramatically in 2009, when he began playing financial officer Lane Pryce in Mad Men . Using his own wry, smooth English tones for once, he gave a performance that blossomed before your eyes: a somewhat comical uptight prig acquired tragic dimensions. Arranged in a louche diagonal on a hotel sofa – jeans, blazer, brogues – Harris is swaggeringly good comp.