Hell Bent, the final episode of Doctor Who‘s regular 9th season, grabbed a 21.5 share in the 8PM slot on BBC One Saturday night. While early overnight viewing figures put it at 4.8M, the numbers were slightly inflated by a runover of Strictly Come Dancing which was the top program of the day, according to Doctor Who News. When the precise timing is taken into account, Hell Bent is expected to drop to 4.47M. This is the official finale of Season 9 ahead of the Christmas episode (see trailer below) which brings back Alex Kingston as River Song.

The current season’s overnight average was 4.23M ahead of Hell Bent. Updated figures have been considerably higher. Using the 4.8M figure from last night, Hell Bent would be the 2nd highest rated of the season; at 4.47M, it’s the 4th. The season featured several two-part episodes along with the departure of Jenna Coleman as the companion and an arc that included Game Of Thrones‘ Maisie Williams.

Hell Bent, which also aired on BBC America last night (viewing figures to come later in the week), has been met with great praise in the UK. This is Peter Capaldi’s second full season as the Time Lord. Without giving anything away, the episode featured the return of some familiar faces.

Season 9 kicked off in September with 4.58M in the UK overnights. That repped a more than 2M viewership dip from the Season 8 premiere which was the first full episode to feature Capaldi; it also reflected increasing time shift trends in the UK. On BBC America, that same episode picked up 2M total viewers in live and same day — the biggest U.S. season premiere ever.

The Christmas episode airs on December 25 and will see the Doctor hiding from carols and comedy antlers on a remote human colony. When a crashed spaceship calls upon him for help, he finds himself recruited into River Song’s squad and hurled into a fast and frantic chase across the galaxy. Kingston first appeared on the show in 2008. Matt Lucas also guests. Check out the holiday-themed teaser: