Ellie Kendrick
Ellie Kendrick - Meera Reed
The Actor: A fast-rising young actress who played Juliet at the Globe Theater at 19, Kendrick is probably best known as Carey Mulligan's best friend in "An Education." She also played the title role in a BBC version of "The Diary Of Anne Frank," and has more recently appeared in TV series "Upstairs Downstairs" and "Being Human."
The Character: The older sister of Jojen, Meera is a skilled huntress who, with her brother, assists and accompanies Bran on his flight from Winterfell.  

Kristofer Hivju
Kristofer Hivju - Tormund Giantsbane
The Actor: A mightily bearded Norwegian actor, Hivju played Jonas, a nervous scientist, in last year's remake/prequel of "The Thing." Since then, he's been shooting a role in M. Night Shyamalan's "After Earth" alongside Will Smith.
The Character: Tormund is a giant-slaying wildling raider, one of Mance Rayder's most trusted men, with the impressive title "Tall-talker, Horn-blower and Breaker of Ice, Husband to Bears, the Mead-king of Ruddy Hall, Speaker to Gods and Father of Hosts." Um, husband to bears?

Philip McGinley
Philip McGinley - Anguy
The Actor: Liverpool-born McGinley has had all kinds of TV and theater roles in his ten years as an actor, but is best known for playing Tom Kerrigan on long-running soap "Coronation Street" between 2008 and 2009. More recently, he had a tiny role in "Prometheus."  
The Character: A talented archer, Anguy is another member of the Brotherhood Without Banners.

Anton Lesser
Anton Lesser - Qyburn
The Actor: A veteran Shakespearean actor, 60-year-old Lesser has long been associated with the Royal Shakespeare Company, and has been a prolific, if somewhat unsung, TV actor in Britain. Most recently, he cropped up in the fourth "Pirates of the Caribbean" and stole the show in excellent BBC program "The Hour."
The Character: A former maester and skilled physician, Qyburn was stripped of his position after performing experiments on living people. Since then, he's joined the mercenary band The Brave Companions.