Duke Ellington was a 20th century Earth musician.
Duke Ellington appeared at 1929 New Year's Eve celebrations at Times Square. (PROSE: New York Record [+]Doctor Who online fiction (BBC, 2007).)
When the American Federation of Musicians went on strike from 1942 to 1944, Ellington could not record his music during that time. In the parallel universe that the Seventh Doctor, Ace and Ray Morita visited, the strike did not take place, thus creating records that did not exist in our universe. (PROSE: Atom Bomb Blues)