London(CNN) Staff working for the British royal family have been summoned to a meeting in London, according to a royal source.
The meeting will take place at 10 a.m. (5 a.m. ET). CNN understands that the subject of the meeting is "significant" but that there was no cause for alarm.
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It is normal for royal staff to be first informed of any significant news regarding the royal family, before a public announcement.
The meeting of senior staff was called by the Lord Chamberlain, the most senior member of Queen Elizabeth II's household staff.
These types of meetings occur once or twice a year. But the manner in which the latest one was called, with such short notice and a day after the UK Parliament was dissolved ahead of a June general election, appeared unusual.
The Queen, who is 91, met British Prime Minister Theresa May at the palace Wednesday as a formality to mark the dissolution of parliament. Britain now has no members of parliament, but government ministers retain their roles.
Also on Wednesday, 95-year-old Prince Philip was photographed during an event at the Lord's cricket ground in London.