Her Majesty Queen Elizabeth II will no longer be attending a centenary service in Northern Ireland's ecclesiastical capital on Thursday, after being advised by doctors to rest.
The Queen was scheduled to attend the Service of Reflection and Hope at St Patricks Church of Ireland Cathedral, Armagh as part of a two-day trip to Northern Ireland starting on Wednesday.
A statement from Buckingham Palace says Her Majesty 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."
The service, due to be held on 21st October has been organised by the Church Leaders' Group (Ireland) to mark the centenary of the partition of Ireland, and the formation of Northern Ireland in 1921, with an emphasis on the common Christian commitment to peace, healing and reconciliation.
The Church Leaders' Group (Ireland) comprises the Roman Catholic and Church of Ireland Primates of all Ireland, the Moderator of the General Assembly of the Presbyterian Church in Ireland, the President of the Methodist Church in Ireland and the President of the Irish Council of Churches. All of these represent all-Ireland denominations with churches across the whole of the island of Ireland.
In a statement, it expressed its regret that Her Majesty would be unable to attend the event: "We wish to convey to Her Majesty our good wishes and, in doing so, to acknowledge the significance of her commitment to the work of peace and reconciliation, which has meant a great deal to people throughout this island.
"We hope that tomorrow's service will provide an opportunity to further that work, with an emphasis on our shared hopes for the future."
The 95-year-old monarch is said to be in good spirits, but disappointed not to be able to carry out the two-day trip.
The news comes just days after she was seen using a walking stick at a major public event when attending a Westminster Abbey service marking the centenary of the Royal British Legion, an armed forces charity.
