Game Of Thrones will be back for its third season on March 31, 2013, it was announced today at Comic-Con. Also announced was that Diana Rigg has officially joined the HBO fantasy drama. Rigg, the star of 1960 TV spy series The Avengers, will play Olenna Redwyne the Queen of the Thorns and is one of several actors to join the fantasy drama this upcoming season. Richard Dormer, Pirates Of The Caribbean regular Mackenzie Cook have also joined the show it was revealed in a video shown to Hall H this afternoon. The new castmembers were made known after a Season 2 highlights video was played. George R.R. Martin, author of the books on which the series is based, moderated the panel that included series regulars Alfie Allen, Emilia Clarke, Michelle Fairley, former Downton Abbey regular Rose Leslie, Kit Harington and Richard Madden. Executive producer Carolyn Strauss also appeared. As if to illustrate the turnover on a show on which a lot of characters are killed off, Clarke, who plays Daenerys Targaryen, is the only member of the cast to return to Comic-Con from last year. The absence of a number of the show’s other main cast was due to the series being deep into filming on Season 3, according to Martin. A source tells Deadline that Game Of Thrones has filmed nearly two episodes of the new season.

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