Schiller's Spotlight page confirms that he will play a character known as Uncle in a future episode, while Berrington's CV at United Agents has also been updated to include the role of Auntie.
Schiller previously played the recurring role of the psychic Hennessey in Being Human and made a guest appearance in the second series of Ashes To Ashes. He will also star in the forthcoming remake of Brighton Rock.
Waterloo Road actress Berrington previously starred in ITV comedy Moving Wallpaper and also appeared in five episodes of Psychoville.
The pair will appear in an instalment directed by Richard Clark, who previously helmed the episodes 'Gridlock' and 'The Lazarus Experiment'.
The sixth series of Doctor Who is expected to launch on BBC One later this year.