The first set photos from House of the Dragon released on Wednesday show that the prequel will borrow some elements from the Game of Thrones TV series as well as the source material books. This hint comes from the photo of actor Rhys Ifans as Lord Otto Hightower, who will be Hand of the King when the series begins. He wears the same brooch to signify his office that characters on Game of Thrones wore, though it may not be accurate to the books.
In George R.R. Martin's novel series A Song of Ice and Fire, the Hand of the King typically signifies their office by wearing a stylized hand of some kind in their jewelry or livery. The first book says that Ned Stark used a silver "clasp that clutched at the folds of his cloak," but after that, both Tyrion and Tywin Lannister chose to wear an ornate golden chain wrought to look like many hands clasped together around their necks. Fire and Blood — the book that House of the Dragon is based on — seems to imply that Otto Hightower chooses the same kind of symbol, since it makes a few references to his "chain of office," including the dramatic line: "Summoning Ser Otto to the throne room, he tore the chain of office from his neck and tossed it to [another character]."
It's a small change, if it was made at all — I can't claim to have re-read Fire and Blood in its entirety for the sake of this article, but a quick search of my ebook edition only shows mentions of Otto's "chain of office." This is another instance where House of the Dragon is bound to show more detail than Fire and Blood, since the book is written as a history, not a narrative, and therefore skips some of those painstaking details.
The brooch not likely to impact the story negatively, and in fact will probably turn out to be a positive change if not a neutral one. Fans will recognize the pin from Game of Thrones, helping them establish some continuity and connections in this unfamiliar setting. It may also be a practical choice for filming, to cut down on jangling chains and swinging costume pieces. Still, it's a clear sign that this show is taking cues from its TV predecessor in addition to its book source material.
Elsewhere in the books, the symbols of two other Hands of the King are described specifically — Lord Rogar Baratheon wears a golden brooch shaped like a hand when he serves King Jaehaerys Targaryen and Bryden "Bloodraven" Rivers wears an iron brooch in The Tales of Dunk and Egg novellas. Other than that, there are only a few quick references to the fashion choices in Fire and Bood and The World of Ice and Fire.
Hopefully, critics of Game of Thrones Season 8 can abide this apparent nod to the other show in the new spinoff, which many are optimistic about. House of the Dragon is filming now in the U.K. and is expected to premiere sometime in 2022 on HBO. If you want to read up ahead of time, Fire and Blood is available here on Amazon in print, digital and audiobook formats.