Thisbe

Thisbe was a character in William Shakespeare's play A Midsummer Night's Dream.

While discussing the play, the Fourth Doctor suggested that he could play Thisbe and Romana II could play Pyramus, though wondered aloud if it was "the other way around". This left K9 Mark II with the part of the Lion, something he was very displeased about. (PROSE: A Midsummer's Nightmare)

Behind the scenes
Pyramus, Thisbe and the Lion actually originate from a tale in Ovid's and do not properly appear in A Midsummer Night's Dream. Instead, they are treated as fictional with other characters in the play portraying them by acting out the story.