Wallis Simpson

 was the divorced American mistress and later the wife of the former King Edward VIII of the United Kingdom.

In November 1936, Lady Louisa Pollard referred to her as "that dreadful Simpson woman." (AUDIO: The Fall of the House of Pollard)

She met the Sixth Doctor and Peri Brown in December 1936, with Winston Churchill expressing his concerns about her close relationship with Joachim von Ribbentrop. She was part of a plan by the Count and Countess to capture Peri, the Players having claimed to von Ribbentrop that she was an agent of the United States Secret Service, but Peri escaped thanks to the aid of Tom Dekker. Edward abdicated the British throne to marry her on 10 December of that year. (PROSE: Players)

In an alternative timeline in which Nazi Germany won World War II, Edward VIII was restored to the throne with Wallis as his Queen in 1940. He signed a treaty which established Great Britain as a protectorate of the Greater German Reich. (PROSE: Timewyrm: Exodus)

Behind the scenes
The Brilliant Book 2011 claims that Simpson was a shape-shifter.