Hans Christian Andersen

Hans Christian Andersen was a human writer. The First Doctor gave him the idea for one of his stories, The Emperor's New Clothes. (TV: The Romans)

As proven by the actions of Nereus, mermaids were only peaceful in the world of Hans Andersen. (AUDIO: Cryptobiosis)

Behind the scenes
According to The Brilliant Book 2012, Andersen was available on social-networking sites and was friends with Charles Dickens in River Song's World.