Ben Elton appeared as the host of Nozin' Aroun' and as one of the Footlights as well as the guy in the beer commercial and one of the Grange Hill kids.
Dawn French and Jennifer Saunders played two different characters in "Interesting" and "Time".
Actor Allusion: In the episode University Challenge the challengers from "Footlights College, Oxbridge" are played by Ben Elton, Stephen Fry, Hugh Laurie, and Emma Thompson. Thompson, Fry and Laurie know each other from their time in the Footlights Club at Cambridge University, and the plotline was inspired by Fry's appearance on the real University Challenge in his student days. "Bambi", whose bias toward Footlights College drives this part of the plot, is played by Griff Rhys Jones, who was also in the Footlights Club. (The real life Bamber Gascoigne was a member in the 1950s too.)
Ade Edmondson, who played bloody, violent Vyvyan, is much nicer in contrast to his character, and says he only ever gets violent when drunk, and would never reach Vyvyan's levels. He's also famously easy to work with, and asks his fellow actors exactly what they'd ask from him to make it easier to do. When Rik Mayall died, he offered an honest goodbye to his old friend, and even included one last heartwarming joke just because he knew Rik would like it.
Rik Mayall was also famously easy to work with, and did many charity runs because of his fame, in part because of what it would draw because of him, and also to show he wasn't like Rick at all.
Lenny Henry as the fascist postman in the last episode, "Summer Holiday".
Jennifer Saunders as Helen Mucus ("Time") and again in "Interesting" as Sue, and Dawn French as the Easter Bunny, the Christian who barges into the house before getting squashed by a giant sandwich and Satan.
Paul Merton makes a very brief appearance as a yokel in "Time".
RobbieColtrane as a bouncer in the second episode, "Oil", and a scientist is one of the odd asides.
He's also the pirate Captain Blood, in Time.
Griff Rhys Jones as 'Bambi' Gascoine, alongside Mel Smith as the front-desk guard.