Jon Hamm admits his on-screen smoking is ''debilitating''.
The 41-year-old 'Mad Men' actor has to plough his way through a raft of herbal cigarettes in his role as advertising executive Don Draper, and says the smoke takes its toll.
He said: ''Someone actually watched the pilot and counted the number of cigarettes I smoked in that episode and it was something like 74.
''You can hear it in my voice, it is a debilitating endeavour. But we're being realistic - people did smoke back then. My father smoked everywhere, even in the car, in the summertime, with the windows up - it was part of life.
''I have read that watching the show makes some people at home want to smoke and drink. I think, well, knock yourself out.''
The former school teacher - who has been dating actress Jennifer Westfeldt for 15 years - also confesses that like most performers, he is riddled with ''self-doubt''.
He told the Metro newspaper: ''Being an actor is a wonderful exercise in self-doubt and regret. I am constantly kicking myself, thinking I should have done this better, or I could have done that a different way.
''That is partly because we work at an incredibly fast pace when we make the show but I am also no different to any other actor - I am constantly revelling in self-doubt.''