The Queen has cancelled a trip to Northern Ireland today and has "reluctantly accepted medical advice to rest for the next few days", Buckingham Palace has said.
A statement from the palace on Wednesday read: "The Queen has reluctantly accepted medical advice to rest for the next few days.
"Her Majesty is in good spirits and is disappointed that she will no longer be able to visit Northern Ireland, where she had been due to undertake a series of engagements today and tomorrow.
"The Queen sends her warmest good wishes to the people of Northern Ireland, and looks forward to visiting in the future."
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Her Majesty's decision is understood not to be related to coronavirus.
It comes after the monarch, 95, hosted a reception at Windsor Castle for international business and investment leaders to mark the Global Investment Summit on Tuesday evening.
She was joined by the Prince of Wales, the Duke of Cambridge, the Duke and Duchess of Gloucester and Prince Michael of Kent as they welcomed Prime Minister Boris Johnson and other attendees at her Berkshire residence.
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The Queen hosted a reception at Windsor Castle on Tuesday
Over the weekend, the Queen looked delighted as she joined racegoers at the British Champions Day at Ascot.
And last week, the monarch was joined by the Prince Charles and the Duchess of Cornwall at the opening of the Welsh Senedd. She also attended a special thanksgiving service at Westminster Abbey with the Princess Royal to mark the centenary of the Royal British Legion, where she was pictured using a walking stick in public for the first time in 17 years.
The Queen is resting at Windsor Castle. She is still expected at this stage to attend events linked to the Cop26 climate change conference in Glasgow at the end of the month.
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