Game Of Thrones Mondo Poster

"Game of Thrones" already has one of the most expansive and impressive casts in the history of television. Essentially picking up the slack that "Harry Potter" left in terms of propping up the British acting industry, the show hasn't just made stars (with names like Richard Madden, Kit Harington and Emilia Clarke coming to serious Hollywood attention), but also given great showcases to veteran character actors -- people like Donald Sumpter, Stephen Dillane and Liam Cunningham have given show-stealing turns over the last two seasons.

One wondered after season one how new additions would fit in, but the first-timers blended seamlessly into the ensemble, and the show has continued to become bigger and better. And with the "Game of Thrones" Comic-Con panel taking place yesterday, the new arrivals for season three have been announced. And while there are a few familiar faces there (notably Diana Rigg, who we discussed on Friday), most aren't exactly household names. As such, we've run down the histories of both the actors and the characters (with as few spoilers as possible) of the new arrivals. Read on for more below, and you can watch a video with some of the cast introducing themselves too. As announced yesterday, season three kicks off on March 31, 2013. It's going to be a long eight months...

Diana Rigg
Dame Diana Rigg - Olenna Redwyne, The Queen of Thorns
The Actor: As detailed last week, Diana Rigg is a true geek icon, thanks to playing the cat-suited secret agent Emma Peel in the British TV series "The Avengers" (a role later taken by Uma Thurman in the disastrous 1998 film version). From that, she also played the only woman James Bond ever loved, killed just after their wedding, in "On Her Majesty's Secret Service." Since then, she's been a staple in film, TV and theater, with her most recent movie appearance being in 2006's "The Painted Veil."
The Character: Olenna Tyrell (née Redwyne), is the grandmother of season two addition Margaery Tyrell, described as a cunning, manipulative matriarch who comes to King's Landing to oversee her granddaughter's wedding to King Joffrey.

Clive Russell
Clive Russell - Brynden Tully, The Blackfish
The Actor: The 67-year-old Scottish actor Clive Russell certainly has his geek bona fides: he starred in Neil Gaiman's TV series "Neverwhere" as villain Mr. Vandemaar and also had a recurring role as sinister comics boss Damien Knox in Edgar Wright's "Spaced" back in the day. He's got over a hundred credits to his name, but the most recognizable one of late is as Captain Tanner in both Guy Ritchie "Sherlock Holmes" films.
The Character: Brynden is the uncle of Catelyn Stark (née Tully), a famous knight who now fights alongside Robb, becoming one of his most trusted advisers and comrades.

Tobias Menzies
Tobias Menzies - Edmure Tully
The Actor: Another familiar face, Tobias Menzies is a RADA grad best known at first for playing Brutus in another HBO epic, "Rome," before being M's right-hand man (before Rory Kinnear took the part) in "Casino Royale." Most recently, he starred in "The Recruiting Officer" at the Donmar Warehouse in London.
The Character: Catelyn's younger brother, Edmure, is a whoring, hot-headed figure, but good at heart. **Spoiler** He becomes the lord of Riverrun after his father, Hoster Tully, dies.

Mackenzie Crook
Mackenzie Crook - Orell
The Actor: Arguably the most recognizable face of the new additions, Crook came to fame as Gareth on the original BBC version of "The Office," before going on to be comic relief across the original "Pirates of the Caribbean" trilogy. More recently, he's had some serious plaudits for his theater roles: first in "The Seagull" with Kristin Scott Thomas, Chiwetel Ejiofor and Carey Mulligan, then the award-winning "Jerusalem," and most recently "The Recruiting Officer" alongside Menzies.
The Character: Orell is one of the lieutenants of Mance Rayder (the biggest part yet to be cast), the so-called King of the North. He's a skinchanger, which means he's able to shift his consciousness inside an animal, in his case an eagle.