Pirates Of The Caribbean star Mackenzie Crook will make a guest appearance on the new series of BBC One’s Merlin.

Crook will play creepy Cedric, who is out to undermine Merlin and ingratiate himself with Prince Arthur.

Cutting It actress Sarah Parish, Hustle’s Adrian Lester and Charles Dance will also show up throughout the series.

A BBC source said: “Mackenzie is a great addition to the cast and fans will be unsure whether he is a goody or baddy. Only time will tell. He is one of whole host of stars signed up for this new run.”