The flurry of casting announcements for HBO's Game of Thrones continues with word directly from author George R.R. Martin that another role has been filled for the second season of the Emmy-nominated drama.

Veteran English actor Oliver Ford Davies, perhaps best known as Amidala's adviser Sio Bibble in the Star Wars prequels, will again play an adviser, this time Maester Cressen of Dragonstone.

In the world of Martin's A Song of Ice and Fire epic, maesters are an order of scholars, scientists and healers trained at a school in Oldtown called the Citadel. Like the Night's Watch, maesters are sworn servants of Westeros and, at least in theory, have no political allegiances. Viewers of Game of Thrones have already seen a handful of maesters, notably Grand Maester Pycell of King's Landing (Julian Glover), Maester Amon of the Night's Watch (Peter Vaughan) and Maester Luwin of Winterfell (Donald Sumpter).

Cressen is a loyal adviser to the self-proclaimed King Stannis Baratheon who becomes troubled by the influence the priestess Melisandre exerts over Stannis and his wife.

Davies joins new additions Liam Cunningham as Davos Seaworth, and Stephen Dillane and Carice van Houten as Lord Stannis and Lady Melisandre.

The producers and stars of Game of Thrones will appear Thursday at Comic-Con International in a panel moderated by Martin himself.