David Walliams is joined by award-winning comedian Jack Whitehall. The episode includes Jack and David's inappropriate take on Sherlock and Watson, the world's worst dating show contestant and Jack doing something David has never done before - dressing as a woman. There is also the launch of Britain's cruelest reality TV show Celebrity Slammer, in which David finds himself locked up with the Chuckle Brothers.

David Walliams has invited comedian Harry Enfield to be his 'Friend' and the result is a masterclass in sketch. Together they appear as John Torode and a rather fussy Gregg Wallace in MasterChef, portray a hilarious pair of ageing lotharios and take a look back at some of Harry's comedy characters that never saw the light of day, until a certain David Walliams got his hands on them.

David Walliams is joined by stage and TV actress Sheridan Smith, who transforms into a real-life Barbie doll, faces an unlikely dilemma whilst filming a swords-and-sorcery epic and hits all the wrong notes as a cruise ship singer with a chip on her shoulder.

David Walliams is joined by actress, writer and comedian Meera Syal. Together for the first time, these two classic sketch performers introduce us to the sadly disappointing pleasure robots of tomorrow. They also play a squabbling husband and wife, a struggling actress auditions for the role of background extra in the evening news, and a robber meets his match in the BBC's newest police drama Good Cop, Indian Mum Cop.

Sketches feature a pair of obnoxious estate agents, a couple on the world's most awkward date and an advert for a company that claims compensation for people who have had their feelings hurt in the workplace.

There is also a viewer who loves Ant but hates Dec and an obstinate shopper who refuses to pay 5p for a carrier bag, while a middle-class Jeremy Kyle tackles a man who leaves the lid off the biscuits.

In this extended episode, star of Downtown Abbey and W1A Hugh Bonneville partners with David Walliams for a variety of comedy sketches. Hugh demonstrates his comic versatility as he plays roles as diverse as Alan Sugar, dishing out the hardest ever Apprentice tasks, and even the Countess of Grantham in her new commercial. In addition, Hugh and David pair up to play smarmy game show hosts of the completely baffling 'Double or Nothing', the world's most embarrassing dancing dads and even Bruce Wayne and his loyal butler Alfred. Also features mini festive episodes of Middle Class Jeremy Kyle and Celebrity Slammer.