The Daily Mail newspaper reported that servants from royal residences across the country had been ordered at late notice to London for a meeting Thursday morning led by the most senior official in the royal household, the Lord Chamberlain.
A palace spokesman refused to comment when questioned about the report by AFP, but speculation spread on social media -- and a few curious royal watchers joined more than a dozen cameras outside the gates.
"I just got here because my cousin got in touch with me from LA. And he said there was something going down in the palace," said 40-year-old American Kim Tatum, an actress.
The queen, 91, returned to the palace on Wednesday after spending the Easter break at Windsor Castle.
She met with Prime Minister Theresa May during the afternoon, to mark the dissolution of parliament ahead of the June 8 snap general election.
Her husband Prince Philip, who will be 96 in June, opened a new stand at Lord's cricket ground.
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