In a statement, the palace said the Queen has been advised to rest for the “next few days.”
A source close to the palace told CNN that it is “not Covid related.”
“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 statement said.
“The Queen sends her warmest good wishes to the people of Northern Ireland, and looks forward to visiting in the future,” it added.
This is a developing story and will be updated.