#Why Brit actor can’t play William in Kristen Stewart-Princess Diana film

The UK’s royal family will no longer be British — at least not in one upcoming major movie.

A new film starring US actress Kristen Stewart as Princess Diana cannot hire a British actor in the key role of a young Prince William because of Brexit, according to a casting notice.

Casting director Amy Hubbard tweeted an appeal for a young actor to “believably play Prince William at 11 years old” for “Spencer,” an upcoming docudrama about the late Lady Di.

“Must have a European passport (NOT British European due to new Brexit rules from January 1st 2021),” the appeal noted of the film being shot in Germany next year when Britons will no longer have Europe-wide work rights.

So far, 30-year-old “Twilight” star Stewart is the only actor confirmed for the upcoming film, with other key royals in her life-story including ex-husband Prince Charles and William’s brother Harry not listed on IMDB.

While the casting call only noted the issue for William, its blame of new European Union (EU) rules after Britain’s formal Brexit suggests the same limitations could apply to other key characters, too.

Hubbard’s tweet sparked a heated debate about the laws, with many actors expressing shock and fears for future roles after Britain formally leaves the EU.

“It’s common on films that the passport for significant characters needs to match that of the financiers,” Hubbard later explained.

“Wherever finance is from, some of the important roles will need to have same passport / citizenship. It’s not to do with visa / travel / admin / red tape,” she added of the movie by Berlin-based Komplizen Film.

“Depressing all the same,” she admitted.

“Spencer” focuses on Diana over three days during the Christmas period in the early 90s when she is said to have realized her marriage was over.

Stewart’s casting has already sparked a backlash among many royal fans — and the American actress recently admitted that learning Di’s posh English accent is “intimidating as all hell.”

“People know that voice, and it’s so, so distinct and particular,” she told InStyle for its November cover story.

“It’s one of the saddest stories to exist ever, and I don’t want to just play Diana — I want to know her implicitly,” she told the mag. “I haven’t been this excited about playing a part, by the way, in so long.”