James Callis and Lindsay Duncan to appear in Merlin

Actors James Callis and Lindsay Duncan are to appear in the fourth series of Merlin.

BBC One’s fantasy drama Merlin will return to BBC One for its fourth series next month and two new guest-stars for the season have been revealed. James Callis is to appear in the fifth episode of the new season as Borden, an old pupil of Gaius (Richard Wilson). The actor is probably best known for playing Dr. Gaius Baltar on Syfy’s re-imaged Battlestar Galactica. Since the series ended Callis has added several other sci-fi roles to his name with stints on Flashforward and Eureka. Callis has also signed up for a role on Ron Moore’s new drama 17th Precinct which will see him reunited with fellow Battlestar Galactica actors Tricia Helfer and Jamie Bamber.

Lindsay Duncan will appear in the fourth episode as Queen Annis. The actress played Capt Brooke in the Doctor Who special The Waters of Mars. Perhaps her most famous role of recent years though was as Servilia of the Junii in HBO/BBC drama Rome. Duncan played Margaret Thatcher in the 2009 film Margaret and also appeared in Lost in Austen, Christopher and His Kind, Marple and narrated Come Fly With Me; the airport comedy by Matt Lucas and David Walliams.