Donald Duck

Donald Duck was, depending on whom was asked, either a cartoon character or a real performer.

When the Fourth Doctor hosted Disney Time, he asked a passerby if he knew where Mickey, Donald and Goofy were. The passerby identified them as "Disney toons." The Doctor, however, then spoke of how he once knew Mickey Mouse personally. He then introduced a clip from the Disney cartoon Clock Cleaners, which featured the trio. (TV: Disney Time)

At Castle Extremis, Martha Jones jokingly introduced the Tenth Doctor as "Doctor Donald Duck", after he in turn introduced her as "Martha Mouse". (PROSE: Martha in the Mirror)

Donald was featured on a postcard alongside Mickey Mouse stuck to a refrigerator in Rani Chandra's house. (TV: The Mark of the Berserker)