<P> 8 Out of 10 Cats Does Countdown is a crossover between the panel games 8 Out of 10 Cats and Countdown . The show follows the format of Countdown, but with hosts and contestants from 8 Out of 10 Cats, and an emphasis on humour . </P> <P> The first episode aired as part of Channel 4's "mash - up night" on 2 January 2012; the first full series was aired in July 2013 and multiple series have since been commissioned . Episodes feature Jimmy Carr as host; two teams of two contestants feature in most episodes, with Sean Lock and Jon Richardson as permanent team captains (various other personalities, such as Lee Mack, Sarah Millican, Bill Bailey and Claudia Winkleman, deputise when either captain is unavailable to film). Rachel Riley and Susie Dent take up their regular roles from Countdown; Joe Wilkinson appears in many earlier episodes as Rachel's assistant and has also stood in as a team captain . </P> <P> On 2 January 2012, Channel 4 orchestrated a special "mash - up night" to celebrate its 30th anniversary, which involved two shows on the network merging their formats . One combination depicted Countdown and 8 Out of 10 Cats . Jimmy Carr took over as host alongside Rachel Riley . Sean Lock and Jon Richardson competed as contestants and Joe Wilkinson joined Susie Dent in Dictionary Corner . The show consisted of four letters rounds, two numbers rounds and the conundrum, interspersed with 8 Out of 10 Cats - style banter . </P> <P> A second special episode called 8 Out of 10 Cats Does Countdown was broadcast on 24 August 2012 as part of Channel 4's "Funny Fortnight". Once again, Carr was host, Lock and Richardson were contestants, and Riley and Dent returned to their roles . In Dictionary Corner, Susie was joined by David O'Doherty . Wilkinson and past contestant Clarke Carlisle also featured . In this edition, there were five letters rounds, four numbers rounds and a conundrum . </P>

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