BBC announce cast for Atlantis, the new drama to replace Merlin The cast includes acclaimed actress Juliet Stevenson, who will soon be seen in BBC One's The Village, Sarah Parish, who has appeared TV dramas such as Mistresses and Monroe and Game of Thrones' Mark Addy. Like Merlin, Atlantis will revolve around a male protagonist, Jason, who arrives in Atlantis and begins a series of adventures. The new BBC series is created by Misfits writer Howard Overman. Merlin producers Johnny Capps and Julian Murphy will be executive producing the 13-part series. Atlantis is based on the Greek myths and legends and will be filmed on two seperate sets which are being constructed in Wales and Morocco ahead of filming in April.