HBO has released the first official teaser footage for its upcoming Games of Thrones prequel, House Of The Dragon, which has been filmed in Hertfordshire.

The first look trailer features a glimpse of former Doctor Who and The Crown star Matt Smith as Prince Daemon Targaryen.

A voice can be heard saying: “God. Kings. Fire. Blood. Dreams didn’t make us kings. Dragons did.”

Based on George R.R. Martin’s 'Fire & Blood', the HBO original series is set 200 years before the fall of the throne and tells the story of House Targaryen.

While Game of Thrones was largely filmed on location in Northern Ireland, its prequel House Of The Dragon has been based in Hertfordshire, at Warner Bros. Studios Leavesden and its huge backlot.

House Of The Dragon is coming to streaming service HBO Max in 2022.

HBO Max is not available in the UK, and upcoming fantasy drama House Of The Dragon will debut here on Sky Atlantic and streaming service NOW next year.

The teaser clip features the first official footage from the highly anticipated GoT prequel.

As well as Matt Smith, the cast includes Emma D’Arcy, who appeared in Nick Frost and Simon Pegg's supernatural series Truth Seekers which was filmed on location in Welwyn Garden City, Steve Toussaint, Olivia Cooke and Rhys Ifans.

Emma plays Princess Rhaenyra Targaryen, the king’s first-born child. She is of pure Valyrian blood, and she is a dragonrider.

Welwyn Hatfield Times: Emma D’Arcy as Princess Rhaenyra Targaryen and Matt Smith as Prince Daemon Targaryen in season one of House of the Dragon.Emma D’Arcy as Princess Rhaenyra Targaryen and Matt Smith as Prince Daemon Targaryen in season one of House of the Dragon. (Image: Ollie Upton/HBO)

Matt Smith's character, Prince Daemon Targaryen, is the younger brother to King Viserys and heir to the throne.

A peerless warrior and a dragonrider, Daemon possesses the true blood of the dragon.

Steve Toussaint stars as Lord Corlys Velaryon.

Welwyn Hatfield Times: Steve Toussaint as Lord Corlys Velaryon, 'The Sea Snake', in HBO's House of the Dragon.Steve Toussaint as Lord Corlys Velaryon, 'The Sea Snake', in HBO's House of the Dragon. (Image: Ollie Upton/HBO)

As 'The Sea Snake', the most famed nautical adventurer in the history of Westeros, Lord Corlys built his house into a powerful seat that is even richer than the Lannisters.

House Velaryon, a Valyrian bloodline as old as House Targaryen, claims the largest navy in the world.

Olivia Cooke will appear in House Of The Dragon as Alicent Hightower.

She is the daughter of Otto Hightower, the Hand of the King, and the most comely woman in the Seven Kingdoms.

She was raised in the Red Keep, close to the king and his innermost circle, and possesses both a courtly grace and a keen political acumen.

Welwyn Hatfield Times: Olivia Cooke as Alicent Hightower and Rhys Ifans as Otto Hightower in HBO's House of the Dragon.Olivia Cooke as Alicent Hightower and Rhys Ifans as Otto Hightower in HBO's House of the Dragon. (Image: Ollie Upton/HBO)

Playing Otto Hightower is Rhys Ifans. As the Hand sees it, the greatest threat to the realm is the king's brother, Daemon, and his position as heir to the throne.

The teaser trailer also introduces newly revealed cast members Wil Johnson as Ser Vaemond Velaryon, younger brother to Corlys Velaryon and commander in the Velaryon navy, and John Macmillan as Ser Laenor Velaryon, son of Corlys Velaryon and Rhaenys Targaryen.

Savannah Steyn plays Lady Laena Velaryon, daughter of Corlys Velaryon and Rhaenys Targaryen, and Theo Nate stars as Ser Laenor Velaryon.

The show will also star Paddy Considine as King Viserys Targaryen.

In June, Warner Bros. Studios Leavesden launched three new sound stages, providing 83,000 sq ft of additional production space, including V Stage, the new state-of-the-art virtual production stage.

The cutting-edge V Stage is one of Europe's largest virtual production stages, offering 24,000 sq ft of total space.

The inside features a 7,100 sq ft wraparound virtual production environment, using a matrix of more than 2,600 LED panels integrated with a powerful processing system.

The V Stage has a dynamic motorised ceiling offering an additional 5,500 sq ft of LED panels with eight sections that lift and tilt to provide a greater level of creative scope.

“The launch of V Stage brings a completely new dimension to filmmaking at WBSL, providing an exciting environment in which to deliver a new level of creativity,” said Emily Stillman, senior vice president, Studio Operations, at Warner Bros. Studios Leavesden.

WBSL is now home to 19 sound stages, two water tanks, and an extended backlot covering more than 150 acres on the former Leavesden Aerodrome in Hertfordshire.