The Diadem

The Diadem is a 1969 German short film starring Diana Rigg which was made or at least after she left as Emma Peel in The Avengers.
The Diadem is a silent film, silent in that there is absolutely dialogue.
The name of Rigg’s character is never revealed with IMDb simply listing her character as “Secret agent”.
Therefore it could be easily interpreted that this secret agent Rigg plays may or may not be Emma Peel.
There is no behind-the-scenes information available for this film and it seems that Rigg never talked about it before her passing in 2020.
The word diadem means a jewelled crown or headband worn as a symbol of sovereignty.
The Diadem is an enjoyable little film as the secret agent finds the diadem and having to battle against two assailants for it.