Sean Lock and Harriet Kemsley take on special guest team captain Alan Carr and Catherine Tate, while Adam Buxton joins Susie Dent in Dictionary Corner.

Jimmy Carr hosts a festive edition of the combination of the comedy panel show and the long-running words and numbers quiz, with Sean Lock and Bob Mortimer taking on Jon Richardson and Lucy Beaumont. Regular Countdown mathematician Rachel Riley and lexicographer Susie Dent are on hand to adjudicate with guests Adam Buxton and Joe Wilkinson.