The League of Gentlemen and Nighty Night star, Mark Gatiss, has joined the cast of the BBC One drama series Jekyll.

Written by Steven Moffat, the six hour drama from Hartswood Films started shooting in September 2006 and continues until Christmas for transmission in 2007. It also stars James Nesbitt, Gina Bellman, Denis Lawson, Michelle Ryan and Meera Syal.

"I'm thrilled to join the cast of Steven's brilliant interpretation of this classic story and particularly pleased to be working with James Nesbitt," says Gatiss. "I hope to keep my own dark side restrained - at least as long as the filming lasts!"