Hafþór Júlíus Björnsson was the third actor to take on the role of Gregor Clegane (aka "The Mountain"), a role previously played by Conan Stevens in the first season, and Ian Whyte in the second season. Whyte had a brief appearence in the third season premiere, though as a different character.
Izzy Meikle-Small auditioned for the role of Sansa Stark and got down to the final two before losing out to Sophie Turner.
Author George R.R. Martin was asked if he had a resolution or ending to the seemingly endless conflict. He jokingly replied that the next book would just be a description of a cloud of dust or snow being driven by the wind across a vast graveyard full of tombstones.
The show has three Doctor Who (2005) guest stars, each of which participated in two parters: Harry Lloyd (Viserys Targaryen), Iain Glen (Jorah Mormont) and Thomas Brodie-Sangster (Jojen Reed). Both Lloyd and Sangster were in the same episodes; Lloyd and Glen also co-starred in The The Iron Lady (2011).
Benjamin Gur auditioned for the part of Trystane Martel in Season 5.
There is not a single character that appears in every episode.
Derek Halligan was cast as Alliser Thorne but left the show before production began. He was replaced by Owen Teale.
Tamzin Merchant played Daenerys Targaryen in the pilot but was replaced by Emilia Clarke for the series. While the reason for Merchant's departure has not been made public, George R.R. Martin praised her performance as "wonderful" in his blog.
Northern Ireland tourist board do a sight seeing tour to a lot of the filming locations.
For the most part, Season 2 is based on the second novel in the series "A Clash of Kings". However, some of the plot points from later in the season, such as Catelyn releasing Jaime Lannister, and Robb breaking his betrothal to House Frey; are actually taken from the early chapters of the third novel "A Storm of Swords". The writers have also said that, given the length of the third book, they are not likely to finish it in the ten episodes given to each season, so it will likely spill over into the fourth season. It is also likely that the fourth and fifth novels ("A Feast for Crows" and "A Dance with Dragons") may both be used as source material for a fourth and fifth season, as none of the same characters appear in both novels, which are meant to take place simultaneously.
After a brief but memorable appearence as Daario Naharis in a couple episodes of the third season, Ed Skrein quit the show to star in the reboot of The Transporter Legacy (2015) films. Actor Michiel Huisman was chosen to take over the role for the fourth season of the series.
Merited the dubious distinction of the most pirated TV show of 2014 for the third consecutive year, ahead of The Walking Dead (2010) and The Big Bang Theory (2007).
The official words of House Lannister "Hear Me Roar!" are seldom mentioned. Their unofficial motto "A Lannister always pays his debts" is often used, mostly in negative context, meaning that Lannisters always repay unkindness with unkindness.
While the first two seasons roughly cover the novels "A Game of Thrones" and "A Clash of Kings" respectively, the third season covers about two-thirds of the third novel "A Storm of Swords". The fourth season covers the rest of "A Storm of Swords" and chapters from the fourth and fifth novels "A Feast for Crows" and "A Dance with Dragons", and part of the sample chapters of "The Winds of Winter".
In Westeros, bastards (also 'natural child' or 'baseborn') born to nobles are given surnames different than their father's, according to the region they were born in. These surnames are mostly associated with the geographic or climatic features of the respective regions: in the Reach - the bastards' surname is Flowers; in the Westerlands - Hill; in the Iron Islands - Pyke; in the Riverlands - Rivers; in Dorne - Sand; in the North - Snow; in the Vale - Stone; in the Stormlands - Storm; in the Crownlands - Waters. The special surnames apply only to noble-born bastards, who are openly acknowledged by their noble parent. Therefore, bastards both of whose parents are commoners, or noble-born bastards that are unacknowledged by their noble parent (like Gendry) cannot use the special surname. A noble-born bastard can be legitimized by royal decree, thus is considered as trueborn child and changes the surname to the father's. However, the social stigma of the bastard may not always be lifted even after legitimization.
The first season used Northern Inuit dogs, a type specifically bred for wolf-like appearance, to stand in for the direwolves (the Stark's house sigil). However, since direwolves are known to be much larger than normal wolves, real wolves were digitally composited into scenes for season 2. This strained the budget and the schedule, hence why there are only a handful of scenes with Grey Wind (Robb Stark's wolf), Summer (Bran Stark's wolf) and Shaggydog (Rickon Stark's wolf); Ghost, who belongs to Jon Snow, is shown in brief glimpses.
Author George R.R. Martin did not write an episode for Season 5 because he was busy focusing on finishing the sixth book of the series, "The Winds of Winter"
In each of the first four seasons, one king dies: first season - Robert; second season - Renly; third season - Robb; fourth season - Joffrey.
Dominic West and Perdita Weeks were offered major roles.
Ian McNeice played Illyrio Mopatis in the pilot but was unable to appear in the series due to scheduling conflicts. He was replaced by Roger Allam.
In the year 2012, over 160 baby girls in the U.S. were legally named "Khaleesi", after the character in the show, although it is not the character's name (Daenerys) but a title.
In 2014, Emilia Clarke was cast as Sarah Connor in 2015's "Terminator: Genysis". However, Lena Headey had played Sarah Connor in the TV show "Terminator: The Sarah Connor Chronicles". Summer Glau whom played Cameron Phillips in the series had worked with Jewel Staite in the TV series "Firefly" and the feature film "Serenity". Jewel Staite herself had worked with Jason Momoa, whom played Khal Drogo in "Game of Thrones" in the TV series "Stargate: Atantis". In 2011, Jason Momoa succeeded Arnold Schwarzenegger whom played The Terminator, as Conan in the 2011 reboot of the 1982 film "Conan the Barbarian". Richard Madden is the boyfriend of actress Jenna Coleman, whom worked with Matt Smith in "Doctor Who". Matt Smith would later star opposite Emilia Clarke in "Terminator: Genysis" and would work with Lena Headey and Charles Dance in "Pride and Prejudice and Zombies".
Emilia Clarke (the actress who plays Daenerys Targaryen) was doused in so much fake blood during one scene that she got stuck to a toilet seat during a break.
Simon Fisher-Becker was originally set to play the High Septon of the Faith of the Seven, which he confirmed in an interview, but David Verry was cast.