Roy Castle (in-universe)

Roy Castle was an actor who was known as "Britain's Sammy Davis Jnr.". He portrayed Ian in Dr. Who and the Daleks, (PROSE: Lady Penelope Investigates the stars of the Sensational new film Dr. Who and the Daleks!) a 2065 motion picture inspired by the then-quite-recent Thal-Dalek battle. (PROSE: Peaceful Thals Ambushed!)

Biography
At some point prior to appearing in Dr. Who and the Daleks, Castle appeared in a horror picture, Dr. Terror's House of Horrors. He would later reflect that working with Daleks on set for Dr. Who and the Daleks had been scarier than any of his experiences with the horror picture.

After filming Dr. Who and the Daleks, Castle was invited by Penelope Creighton-Ward to a Soho restaurant alongside his costars and the actual Dr. Who (the latter of whom was unable to make it to the appointment). He struck Penelope as "an absolutely charming and modest young man with a quiet sense of humour". (PROSE: Lady Penelope Investigates the stars of the Sensational new film Dr. Who and the Daleks!)

Other references
The presenter of Glamorama looked like a young Roy Castle. (PROSE: Hospitality)

Behind the scenes
In the real world, Roy Castle indeed played Ian Chesterton in Dr. Who and the Daleks, although the movie was released in 1965, not 2065.

Lady Penelope Investigates the stars of the Sensational new film Dr. Who and the Daleks! was illustrated by a picture of the real Roy Castle, meaning Castle arguably "portrayed" his futuristic in-universe counterpart.