Church bells will ring out in Northern Ireland today as the Queen becomes our longest reigning monarch.
The Queen will pass the record set by her great-great-grandmother Queen Victoria who defined an era and left an indelible mark on 19th century British history.
The exact moment the Queen passes Victoria's milestone is not known as there is no precise time for the death of her father George VI, who passed away in the early hours of February 6, 1952.
But it is thought he probably died at 1am so at around 5.30pm the Queen will make history as Buckingham Palace has calculated she will have reigned for 23,226 days, 16 hours and approximately 30 minutes, a few minutes longer than Victoria.
Normal business will be postponed in the House of Commons for half an hour from 11.30am to allow MPs to pay tribute to the head of state.
Special services will be held this evening at St Anne's Cathedral in Belfast and St Columb's Cathedral in Londonderry at 5.30pm to mark the historic moment.
The heads of the Church of Ireland and Presbyterian Church have issued their congratulations to the Queen on her remarkable reign.
Archbishop of Armagh Richard Clarke expressed good wishes and thanks to the Queen.
"In marking this moment, it is an appropriate opportunity to express gratitude to the Queen for her faithful life of service and for her dedicated witness to the Christian faith throughout her long reign," he said.
Presbyterian moderator Ian McNie has written to the Queen on behalf of his church in Ireland to offer thanks for the "selfless and steadfast service that Your Majesty has given throughout those 63 years".
Bells will ring out across the world to mark the Queen's record reign from Westminster Abbey in London to Worcester Cathedral.
In Belfast the historic bells of St Bartholomew's Church of Ireland in Stranmillis will ring out.
These bells date back to the 14th century, and rung for the accession of Queen Elizabeth I in 1558 in their former home, St Patrick's Cathedral in Dublin.
The bells came to Stranmillis in 1938 and in 1945 proclaimed the final victory of the Allied Forces in the Second World War as well as the coronation of the Queen in 1952 and the Diamond Jubilee in 2012.
The Orange Order will celebrate the Queen's long reign by holding a celebratory parade on Sunday and a service at Kilcronaghan Parish Church, Tobermore.
Last night the Finance Minister Arlene Foster hosted an event in Parliament Buildings, Stormont to mark the record service of the Queen.
It was attended by the Lord Lieutenant of Co Down, David Lindsay, and showcased a display of important artefacts which included a throne used by the Queen when she visited Parliament Buildings.