Rachel Riley and Pasha Kovalev, Richard Herring and Catie Wilkins

Comedians Jon Richardson and Lucy Beaumont put their own marriage flaws to one side in order to judge everyone else's, by inviting two unsuspecting celebrity couples to go head to head to decide who has the best relationship. First to respond to the challenge are Countdown maths whizz Rachel Riley and professional dancer Pasha Kovalev, and comedians Richard Herring and Catie Wilkins.