The role was originally played by Tamzin Merchant, who starred in Pride and Prejudice and The Tudors. After filming the pilot episode, Merchant left the show and Clarke replaced her as the feisty dragon queen.
Jack Gleeson, who plays Joffrey Baratheon, is currently studying theology and philosophy at Dublin's distinguished Trinity University. Gleeson has said that after the series ends, he wants to pursue a career in academics rather than in acting.
Oona Chaplin, who plays Robb Stark's wife (apparently her name is Talisa? Did anyone else somehow never catch that?), is the granddaughter of the famous silent film actor Charlie Chaplin. She also dances ballet, salsa, and flamenco.
Bronn, Tyrion's witty sellsword companion, is played by Jerome Flynn, who used to be one half of the British duo Robson & Jerome. The pop stars had three number one singles in the UK in the '90s. I wonder if they ever jam the album on set?
Thomas Brodie-Sangster, who plays the warg Jojen on GoT, is Hugh Grant's cousin, and the two acted together in Love, Actually. Additionally, Thomas is the voice of Ferb on the animated Disney show Phineas & Ferb. Personally, I think the most surprising fact about Brodie-Sangster is that he's barely 25(?!)