Jonas Armstrong, the actor who plays Robin Hood in the BBC remake of the tale, is to quit the show at the end of the third series.
The 27-year-old has become a household name since landing the role and said playing the legendary outlaw had been an "incredible experience" but added that he was looking for "new challenges".
The hit series currently attracts eight million viewers to BBC1 each Saturday, so losing its star will be a big loss to the BBC. However, bosses have confirmed the show will continue without Armstrong.
The Telegraph online quoted an insider as saying: "Jonas might be leaving but there is every intention for a fourth series. We don't want to give away what happens yet but it will be explosive."
Armstrong graduated from the Royal Academy of Dramatic Art in 2003, where he performed in productions including Twelfth Night, The Caucasian Chalk Circle, The Crucible and Ulysses. His television credits include The Ghost Squad, Teachers and Island at War.
The third series of Robin Hood will be shown on BBC1 next year, and will run for 13 episodes.