LONDON -- The Queen of England reportedly called the entire staff for the royal household for a "highly unusual" emergency meeting late Wednesday night.

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Several news outlets are speculating it could be concerning Queen Elizabeth or her husband, Prince Philip, the Duke of Edinburgh.

According to the Daily Mail, staff from across the country have been summoned to the royal palace for the meeting. Senior royal officer Lord Chamberlain and private secretary Sir Christopher Geidt are expected to address staff, but the subject of that meeting is currently unknown.

"Although meetings involving the entire royal household are occasionally called, the way this has been done at the eleventh hour is highly unusual and suggests that there is something major to be disseminated," a source told the Daily Mail. "But at the moment, only those closest to her genuinely know what on earth this is all about."

The Queen, who turned 91 last month, was recently in the public eye when she met with British prime minister Theresa May to mark the dissolution of Parliament due to the general election. She and Prince Philip, who will turn 96 in June, just returned to the palace after celebrating a long Easter holiday.

Buckingham Palace declined to comment on the situation.

This story is developing.

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