It's a bleak midwinter in the Shakespeare household as the family comes to terms with a cruel loss. But when a mysterious stranger (Kenneth Branagh) offers to share with Will a tale of redemption he becomes filled anew with love and light and hope.

Now Will has a mission - to save another soul from despair. He and his family and friends get together to save Greene from a mean and miserly life, and arrange for three midnight "ghosts" to visit him before Christmas.

Who is the stranger? Can Will and his family and friend's efforts persuade Greene to change his ways and show some generosity to his servant Job Scratchit? And at the end of it all could this tale of Yuletide redemption be another smash Shakespeare hit on the stage, or is its time not yet come? In short, what the Dickens is going on?

Kenneth Branagh, talking about guest starring in this episode, said: "This year I fulfilled a much cherished ambition by playing comedy with the brilliant David Mitchell. I have Ben Elton to thank for including me in his blisteringly funny and very touching Christmas special of Upstart Crow. It's a show I love watching and was honoured to join.

"Brilliant cast and crew, brilliant fun, and a huge inspiration for our dramatic film, All Is True (also about Shakespeare, also written by Ben Elton), which opens in cinemas on February 8th. David's Shakespeare is taller, funnier and sexier than mine, but mines is older and fatter, which at least offers you a choice."

David Mitchell commented: "I was incredibly excited and nervous at the prospect of working with Kenneth Branagh, who I have admired for decades, but I'm sorry to say that he was less personally terrifying than I'd expected. He was, though, friendly, easy-going and charming, but at the same time full of funny ideas and brilliant at acting."