Katherine Jenkins stars in Christmas Doctor Who

Doctor Who will be joined by Welsh opera singer Katherine Jenkins as he battles a flying shark in this year's Christmas special. After a preview screening of the new episode on Monday, writer-producer Stephen Moffat joked that he wrote the festive spectacular for an audience who "are probably drunk" - which could explain the plot.

It's a twist on Charles Dickens's classic Christmas Carol, albeit with a crashing spaceship, Albert Einstein and the aforementioned shark thrown into the mix.

Michael Gambon guest stars as Kazran Sardick, the Scrooge-alike who is visited by Matt Smith's Time Lord on another mission to save the planet.

In her first acting role, Jenkins plays Abigail Pettigrew, the love of Kazran's life. Early reviews suggest she showcases her famous voice more than once during the hour long episode. The doctor's newlywed assistants Amy (Karen Gillan) and Rory (Arthur Darvill) also make appearances.

The Doctor Who special has become an annual fixture on the BBC's Christmas Day schedule alongside Eastenders – both of them key weapons in the festive ratings war with ITV.

Doctor Who: A Christmas Carol will be broadcast at 6pm on Christmas Day. ·