A pilot episode, by definition, is a standalone episode of a television series that is used to sell the show to a television network. They are often radically different to what we eventually see on screen, as alterations to the likes of storyline, characters and casting are often made to improve a series with an interesting premise before it is shown to the public. This article focuses on changes in casting, looking at four characters from iconic series that were originally portrayed by different actors before these individuals were replaced by the people we have grown to know and love in the roles. Characters who were recast during the shooting of the pilot episode, such as Sharpe (Sean Bean replaced Paul McGann after he injured himself playing football) or The Incredible Hulk (Lou Ferrigno replaced Richard Kiel when producers decided that the Hulk should be more than just large), or those who were recast after one non-pilot episode, such as Emma Peel (Diana Rigg replaced Elizabeth Shepherd after one episode of The Avengers fourth season had been filmed, introducing the character), have been excluded from this list, which we shall begin now.