After a huge year which saw him tour the world with his latest album, as well as smash the charts with Calvin Harris club thumper Promises, Sam Smith is finishing off 2018 with a brand new song.

The singer-songwriter has recorded huge new ballad Fire On Fire for the BBC’s remaking of Watership Down.

The accompanying music video sees footage of James McAvoy’s Hazel, Nicholas Hoult’s Fiver and John Boyega’s Bigwig as they make an escape from Sandleford Warren.

“I am so excited and honoured to be a part of this new adaptation of Watership Down,” Sam previously said. “This story is so powerful and timeless, and it has been thrilling to work with Noam and his team and the incredible Steve Mac on this song for it. I hope everyone loves it as much as I do.”

The new song was recorded by Sam with the BBC Concert Orchestra at London’s Abbey Road Studios in September 2018.

The all-star cast also includes Olivia Colman, Gemma Arterton, Sir Ben Kingsley, Daniel Kaluuya, Peter Capaldi, Mackenzie Crook, Miles Jupp, and Anne-Marie Duff, who will all voice rabbits in this new screen version of Richard Adams’ classic novel.

Charlotte Spencer, Craig Parkinson, Daniel Rigby, Freddie Fox, Gemma Chan, Henry Goodman, Jason Watkins, Lee Ingleby, Rosamund Pike, Rory Kinnear, Taron Egerton, and Tom Wilkinson also star.

“It’s a real testament to the calibre of this adaptation of Watership Down that it has attracted such an exciting roll call of names to bring these much loved characters to life,” said Ben Irving, Executive Producer for BBC One.

© BBC/Netflix

“Now – in Sam Smith – we have one of the world’s most successful recording artists, with the perfect new song to serve as the series’ theme. BBC One viewers are in for a treat this Christmas.”

The first part of Watership Down will air on BBC One on 22 December at 7pm, with the second part to follow on 23 December at 7:20pm.

They will then both be available to stream on the iPlayer.

This new adaptation is a co-production between BBC One and Netflix, with the streaming giant to premiere Watership Down worldwide outside of the UK.

Related: Sam Smith reveals that he has given up alcohol as he starts to look after his mental health