Casting for the long awaited Game Of Thrones’ prequel House Of The Dragon has begun according to Entertainment Weekly.

The new HBO show, which is expected to be released in 2022, will chart the reign of the Targaryen family in the Seven Kingdoms and is set 300 years before the hit fantasy series.

While the show has begun casting, the publication confirmed that there was no news yet on who had been selected.

The cast in the critically-acclaimed fantasy hit series, “Game of Thrones”. Picture: HBO

According to the publication show veterans Ryan Condal and Miguel Sapochnik, who directed Battle Of The Bastards, will be at the helm of the series.

Although casting news is remaining under wraps, a source told the publication that the famed Dance Of Dragons, the civil war between the Targaryens, will feature, though it’s not clear at which point the show will address that storyline.

HBO handed out a straight to series order for House of the Dragon, which was initially one of the five projects the network was developing. 

While the initial project was written by Game of Thrones writer Bryan Cogman, Deadline reported in September that this is a brand new take on that world, written by Colony creator Ryan Condal.

The show will be based on George R.R. Martin’s Fire & Blood, a companion book released in November 2018, which details the history of House Targaryen.

House Targaryen ruled over Westeros for 300 years, before Robert’s Rebellion ended their reign. 

David Benioff, centre left, and D.B. Weiss accept the award for outstanding drama series for “Game Of Thrones” at the 71st Primetime Emmy Awards on Sunday, Sept. 22, 2019, at the Microsoft Theater in Los Angeles. Picture: AP

In Game of Thrones, Emilia Clarke’s Daenerys Targaryen marked the last of the family, until it was revealed that Jon Snow’s real parents were Rhaegar Targaryen and Lyanna Stark, making him the rightful heir to the Iron Throne.

As HBO was heading into its final seasons of Game of Thrones, it had commissioned five pilots from different writers, though only House of the Dragon moved forward to series.

The network did order a pilot for another project, an untitled Game of Thrones spin-off, set 8,000 years before the events of the show and George R.R. Martin’s books. 

That pilot starred Naomi Watts, Miranda Richardson and Jamie Campbell Bower, to name a few, written by Jane Goldman (Kingsman: The Secret Service) and directed by S.J. Clarkson (The Defenders), but the network passed on bringing it to series. 

Drogon and Daenerys Targaryen played by Emilia Clarke. Picture: Helen Sloan/HBO

Bloys did commend Goldman for ‘beautifully’ building the world of the show, but since it was set so far before the original show, ‘it required a lot more invention.’

‘One of the benefits of House of the Dragon is there was a text from George and there was a little bit more of a roadmap,’ Bloys added.

‘[Goldman’s prequel] did have more challenges in terms of establishing a world, but I think she handled that beautifully… there wasn’t one glaring thing,’ he added.