The Queen (of England, Australia, New Zealand, Canada etc. (Elizabeth II)) was touring Austalia and attended a film premiere.
At the end of the movie, all of the people involved in the production of he film were lined up in he foyer of the theatre. As she walked along the line of people she stopped by one man and asked:
"And what part did you play in the produstion?"
"Well, actually, Your Majesty, I was the photographer"
The Queen (remembering the husband of her sister, Margaret (Anthony Armstrong-Jones)) replied:
"How interesting, I have a brother-in-law who's a photographer."
To which the photographer replied:
"Well what a coincidence. I have a brother-in-law who's a queen"