This looks close to confirmed, although not officially. Kerry Ingram, a young English actor from Warfield (fitting!), has tweeted about getting a role on Game of Thrones.

According to this London Evening Standard article, it appears that British actress Tara Fitzgerald has been cast in season three of Game of Thrones. The article focuses on her athleticism and then drops this line at the end.

According to the website of Shepherd Management, Clive Russell has been cast in the role of Brynden “The Blackfish” Tully.

The English-born and Scottish-raised actor has appeared in many British television shows, including Coronation Street, Middlemarch, and Cracker. His film resume is just as lengthy, with him recently playing Captain Tanner in “Sherlock Holmes: A Game of Shadows.”

HBO will have to confirm before we can call this official, of course.

The Game of Thrones script reading on June 27th kicked off a fresh round of rumors and speculation surrounding the casting for season 3.

• Charlotte Hope has been cast in the role of “Myranda,” according to her CV on Spotlight.com. It’s unclear if this is intended to be the character “Myranda Royce” of the Vale, since her introduction at this point wouldn’t fit the books’ timeline precisely, and she is younger than the character is intended to be. An altered version of Myranda Royce or a completely different character with a borrowed first name, perhaps?

• Mackenzie Crook, of Pirates of the Caribbean and The Office (U.K.) fame, was seen several times in Belfast over the last few days, during the time of the script reading. One local spotted him with Night’s Watch cast members, along with Finn Jones and Joe Dempsie, while another saw him dining at local restaurant Made In Belfast, the same night Emilia Clarke was there. 
• Sarah Bolger, star of The Tudors, has also been spotted in Belfast, as well. Interestingly, she tweeted that she was in Belfast a few days ago, but later deleted that tweet.
• Nathalie Emmanuel, who played Sasha Valentine on Hollyoaks for three years, will be appearing on at least one episode of season 3.  Her role is unknown but she posted a photo on her Twitter of a script with a faint but readable stamp that read “Game of Thrones,” and the cover clearly stated “Episode 306.” (The photo was later taken down.) She also mentioned beginning horse-riding lessons.

Entertainment Weekly’s James Hibberd has the (partial) cast list of characters introduced in Season Three. Reproduced below with original role descriptions:

• Mance Rayder: We’ve heard about him all season. A former member of the Night’s Watch who became the “King Beyond the Wall,” the leader of the Wildlings.
• Daario Naharis: A confident and seductive warrior.
• Jojen Reed; Meera Reed: A teenage brother and sister duo with special insights.
• Edmure Tully: A brash young member of the Tully family

• Olenna Redwyne (The Queen of Thorns): Margaery Tyrell’s sharp-witted grandmother.
• Beric Dondarrion: A skilled knight who is the leader of the outlaw group Brotherhood Without Banners.
• Thoros of Myr: A red priest who follows the same religion as Melisandre.
• Tormund Giantsbane: A Wildling raider.