Diana Ross

During the 1966 Dalek invasion of Earth, the Fourteenth Doctor nicknamed the Supreme Dalek "Diana Ross". He later attempted to explain to the Daleks a pun using her name, comparing "Di Ross" to "Davros". (COMIC: Liberation of the Daleks)

Behind the scenes
In real life, Diana Ross was the lead singer of the American Motown group the Supremes, hence the Doctor's nickname for the Supreme Dalek.