Rhys Ifans has joined the cast of Game of Thrones prequel series House of the Dragon.

The Notting Hill and Harry Potter actor will play a character called Otto Hightower, whom Deadline reports is a loyal servant to Paddy Considine's character King Viserys Targaryen.

Considine's casting in the prequel series was announced in December – along with news that former Doctor Who star Matt Smith will play his brother, Prince Daemon Targaryen. In the eyes of Ifans' Otto Hightower, Smith's Prince is the greatest threat to the realm.

Olivia Cooke and Emma D’Arcy have also previously been cast in House of the Dragon, which tells the story of House Targaryen and takes place 300 years before the events of Game of Thrones.

Along with Ifans, the series has now added three other new cast members: Steve Toussaint (Doctor Who, Death in Paradise), Eve Best (Nurse Jackie), and Sonoya Mizuno (Devs). HBO has ordered a 10-episode first season of House of the Dragon, which is co-created by George R.R. Martin and Ryan Condal. Game of Thrones director Miguel Sapochnik will serve as co-showrunner alongside Condal.

Condal has previously spoken about House of the Dragon's relationship with the enormously successful Game of Thrones series.

"The original [Game of Thrones] series has certain themes, and I think Miguel (Sapochnik) and I found together this thematic that runs very much through the Targaryen dynasty that we are very excited about," he told Winter Is Coming last year. "That to me, gives you the sort of all the familiarity of the original series that people love so much, while having a very different thing to say about the show. Miguel always says ‘If it ain’t broke, don’t fix it.’"

He added: "We’re really trying to approach this show, and honor all of the things that were great about the original, while not just doing a cover of the song you’ve heard before. It’s trying to be original without completely trying to break the box."

Are you excited about House of the Dragon?