Doctor Who and the Python
In 1979 while Doctor Who was filming the story City Of Death at BBC Television Centre John Cleese was busy recording the second series of Fawlty Towers in the next studio. Both Baker & Cleese seemed to get on with each other so the Doctor Who script editor at the time Douglas Adams (Yes, THE Douglas Adams) wrote a small cameo appearance for Cleese along with actress Eleanor Bron, a good friend of Cleese playing the part of a pair of art critics in the Louvre Gallery where the Tardis happened to be parked during this story.
As well as this scene Baker & Cleese also recorded a short comedy sketch that would be put on the BBC's Christmas tape, A tape that was traditionally shown during the BBC's annual Christmas party for it's employees which usually featured out-takes & specially recorded sketches.