George RR Martin has seen a rough cut of House of the Dragon series

The first look at the prequel to the iconic series has been revealed. Photo / Supplied

George RR Martin has seen a rough cut of the 'Game of Thrones' spin-off series 'House of the Dragon' and "loved it".

The 73-year-old author wrote the 'A Song of Ice and Fire' series of books that the HBO fantasy drama was based on, and has now teased the upcoming spin-off series – which tells the story of the Targaryen family – is set to be "amazing".

The first look at the prequel to the iconic series has been revealed. Photo / Supplied

In a post on his website in which he reflected on 'House of the Dragon' being named IMDb's "most anticipated new show" of 2022, he wrote: "Don't tell anyone … I've seen a rough cut of the first episode. And loved it.

"It's dark, it's powerful, it's visceral … just the way I like my epic fantasy."

George went on to praise executive producers Ryan J Condal and Miguel Sapochnik for their work on the series, and said the show was "in very good hands".

He added: "Ryan and Miguel have done an amazing job. And the cast … just as with 'Game of Thrones', most viewers will only have heard of a few of the actors, but I think you are going to fall in love with a lot of them. (Only to have your heart broken later when … but no, that would be telling).

"I think the Targaryens are in very good hands."

Game of Thrones author, George RR Martin. Photo / Supplied

The author concluded his post by telling fans to "anticipate away" ahead of the show's premiere and said, "I do not think you will be disappointed".

'House of the Dragon' follows the Targaryen civil war, which occurred about 300 years before the events that took place in 'Game of Thrones'.

Matt Smith, Olivia Cooke, Emma D'Arcy, Rhys Ifans, Steve Toussaint, Eve Best, Paddy Considine, Fabien Frankel, and Sonoya Mizuno are in the cast.

The first season, consisting of 10 episodes, is slated to premiere on HBO and HBO Max in 2022.