The Royal Family often brush shoulders with famous celebrities and legends of stage and screen, but it is very rare for them to become one of the stars themselves.
While two actresses have previously married into the family, the public are not used to seeing royals dazzle on the silver screen.
The royal rulebook was thrown out in 2009 when Princess Beatrice made a notable cameo in a new film about her lookalike great-great-great-great grandmother, Queen Victoria.
