James Nesbitt

When I was growing up, Belfast City Hall was surrounded by security, and we had no access to it. But now, people come in and out of it all the time. On a nice day, office workers and students sit on the lawn outside and have lunch. It's great to see how Northern Ireland has changed. To be part of that is fantastic.

Frankly, as much as I love to improvise, it hasn't been difficult to stick to the script on 'Mad Men.' The writing is so precise, and the story so carefully crafted, that I don't think there's room - or need - for ad libbing. I could never come up with dialogue as lovely as these writers do, anyway.