Casting director Amy Hubbard has posted a call out for 11-year-old male actors to audition for a role in the new movie, "Spencer", on Twitter, but her followers spotted a stipulation that applicants must have a "European (not British-European) passport".
It is reportedly due to start shooting in Germany early next year.
"We're meeting British boys all the time for this role", Webster told. "If they happen to have an Irish passport all well and good".
"Many of our cast will be British".
This will nearly certainly cause a headache for those in charge of casting the film, but it also means that European children- including those from Ireland- will have the chance to test their skills and play the Prince in the film. Some of our cast will be European to meet certain funding requirements.
A representative for the British Film Institute (BFI) confirmed to the publication that despite there being no post-Brexit agreement between the United Kingdom and European Union, certain United Kingdom and European co-productions with a British cast are expected to be able to shoot on the continent due to the Council of Europe Convention on Cinematographic Co-production.
Notably, though, none of these measures are set in stone until the terms of the UK's departure from the European Union have been confirmed by the government. In an interview with InStyle, she said "The accent is intimidating... because people know that voice, and it's so, so distinct and particular".
On the film Spencer, which will be directed by Pablo Larraín, Stewart described it as a "very poetic and internal imagination" of how Diana's life would have felt in those crucial moments in which the production will focus.
Spencer doesn't yet have a release date, but filming is expected to begin in early 2021.