8 Out of 10 Cats Does Countdown as part of its 30th anniversary celebrations. Amongst the programmes that were chosen to be merged for the evening of specials, production teams on "Countdown" and "8 Out of 10 Cats" agreed to merge the two formats of their respective programmes together - the crossover between the two formats meant that "Countdown"s arrangement of games would be interspersed with "8 Out of 10 Cats"-style banter. As part of the merger, both Rachel Riley and Susie Dent assumed their roles from the programme, while Jimmy Carr took on the mantle of host, with both Sean Lock and Jon Richardson competing as
8 Out of 10 Cats Does Countdown Richardson were joined by an additional contestant each, for each special - Rhod Gilbert, Rob Beckett, Stephen Mangan and Richard Osman - with Dent joined by Tim Key and Henning Wehn respectively during recordings. On 9 July 2013, owing to favourable ratings from the specials, Channel 4 announced its decision to commission a full series of six episodes of the crossover, which was aired from July to September, Following the first series, the network ordered additional series for 2014, 2015, 2016, and 2017. On 13 July 2018, Channel 4 aired a special edition of the crossover series as part of