Game of Thrones” prequel “House of the Dragon” debuted on HBO Max in Europe with the largest ever audience for any new series or movie on a HBO streaming service.

The first episode went live on HBO Max in 21 European countries across the Nordics, Netherlands, Central Eastern Europe and Iberia at 3am CET on Monday.

“The platform saw unprecedented demand starting in the early hours which peaked on Monday evening,” an HBO statement said. Viewing numbers were not provided.

A spokesperson for HBO Max said: “ ‘House of the Dragon’ is by far the biggest launch in the history of HBO and HBO Max in Europe, breaking previous records for a new title. The number of viewers for the first episode exceeded all expectations.”

In neighbouring U.K., “House of the Dragon” proved to be a record breaker for Comcast’s Sky and Sky Atlantic, with 1.9 million tuning in, overtaking “Game of Thrones.”

In the U.S., the premiere of “House of the Dragon” drew nearly 10 million viewers across linear and HBO Max on Sunday night to become the largest audience for any new original series in the history of HBO.

Based on George R.R. Martin’s Fire & Blood, the 10-part series, which will premiere over the coming nine Mondays, is set 200 years before the events of “Game of Thrones” and tells the story of the House Targaryen. The series stars Paddy Considine, Matt Smith, Olivia Cooke, Emma D’Arcy, Steve Toussaint, Eve Best, Sonoya Mizuno, Fabien Frankel and Rhys Ifans.

George R.R. Martin is co-creator and executive producer.