The power of the genre to create new stars - or to spur existing stars on to create some of their most powerful performances. From Mansfield Park's Billie Piper to Helen Mirren in Elizabeth and My Boy Jack's Daniel Radcliffe to Keira Knightley's TV debut in Doctor Zhivago we speak to the stars themselves as well as their fellow actors about what it takes to create these iconic characters on screen - and the rigours of working on such demanding shows.
Did You Know?
Keeley Hawes - Narrator
So what is it that sets a memorable leading actor above all others?
A leading man has to be charming.
I think he's got to be a little bit heroic.
Having that moody, sort of dark, handsome look...
Got to look good in tight trousers.
Sean Bean - trousers on or off - fabulous.