And Professor Sprout as an Infanta of Spain in series 1, Blackadder's aunt in series 2 and Queen Victoria in Blackadder's Christmas Carol.
Three of The Young Ones have also guest starred on the show - Rik (Rik Mayall) as Mad Gerald in series 1 and Flashheart in series 2 and 4, Neil (Nigel Planer) as Smedley, the Scarlet Pimpernel's associate in series 3, and Vyvyan (Adrian Edmondson) as the Red Baron in series 4.
Arnold Rimmer as the French prison guard in Blackadder the Third.
Hagrid plays Dr. Samuel Johnson, inventor of the Dictionary, in series 3. He's also the ghost of Christmas in Blackadder's Christmas Carol.
Major Toht is the Baby-Eating Bishop of Bath and Wells! Eep.
Angus Deayton makes an appearance in season 1.
Doctor Who companion Peri is Millicent in Blackadder's Christmas Carol.
Present in The Black Adder
What Could Have Been: The original pilot episode was much more similar what the later Blackadder installments would be like, but Executive Meddling resulted in the version of The Black Adder that we know and... well, treat as a valued and respected friend, but not really love, per se. Most fans believe that had the finished series combined the pilot episode's characterisations with the cast that we ended up with, it would have been vastly superior.