Episode 1
Five series champions - Josh Widdicombe, Katherine Ryan, Noel Fielding, Rob Beckett and Bob Mortimer - clash, as we find out their most embarrassing items.
Episode 2
Five hall of famers return for more consensual indignity at the hands of Greg Davies. The challenges include making a mask which both looks and tastes great.
Episode 3
Series winners Ed Gamble, Kerry Godliman, Liza Tarbuck, Lou Sanders and Richard Herring bid to become the next Champion of Champions with bath toys, bobbins and bananas.
Episode 4
Former champs Dara Ó Briain, Morgana Robinson, Sarah Kendall and Sophie Duker - and former runner-up Kiell Smith-Bynoe - battle for Greg Davies' buff body forged in gold.