"The Long Night" was dark and full of terrors — and watched by a lot of people.

Sunday night's episode of "Game of Thrones" was not just the longest in the series' history, but also the most-watched. It set a new record for the HBO drama with 17.8 million viewers, including same-day replays and streaming.

That passes the previous record of 17.4 million viewers for the Season 8 premiere on April 14.

The initial airing of "The Long Night" drew 12.02 million people, the second largest behind only the Season 7 finale (12.07 million). The viewership will grow as additional airings and streaming numbers are added through the week.

It was also the most-tweeted episode in TV history.

"The Long Night," directed by Miguel Sapochnik, ran for 82 minutes and was devoted entirely to the Battle of Winterfell, which pitted the living against the Night King and his Army of the Dead. The intense, seemingly hopeless fight culminated with the assassin-trained Arya Stark surprising the Night King and stabbing him a dragonglass dagger, decimating the White Walkers and wights.

"Game of Thrones" airs Sundays at 9 p.m. on HBO.