At the headquarters of 38 (Irish) Brigade in Lisburn, final preparations have been made at the Garrison Church where members of the Armed Forces and their families will gather at 10pm for a service during which the lights will go out one by one until only a candle will remain to light the stained glass window.
Similar services are being held at Palace Barracks in Holywood and at Aldergrove.
The Armed Forces in NI are supporting civic commemorative events being held across Ireland to commemorate the service and sacrifices made by men and women across the services.
One such event is being held in St. Anne’s Cathedral, Belfast, led by Dean of Belfast John Mann.
A candlelit vigil and act of remembrance will be held later tonight at the Cenotaph at Belfast City Hall.
Organiser Jeffrey Donaldson said: “We face a decade of significant centenaries in Northern Ireland and on the island of Ireland and I feel it is important that these should not become divisive.
“The global events that took place during 1914-1918 involved people from across the island and the political divide and had a profound effect on the history of Ireland in the 20th century.
“We owe it to those who sacrificed their lives with such valour to ensure that the centenary is used to promote better understanding between our various traditions on this island.
“The centennial commemorations of the war provide an opportunity to enhance our shared understanding of this history and to promote reconciliation.”
A member of the Royal Family and First Minister Peter Robinson will be present at the commemorative service along with a senior member of the Irish government and other community leaders from across Ireland.
Representatives of the Royal British Legion and regimental associations of the army will also attend.
The candlelit vigil will coincide with a similar event at Westminster Abbey and in other regional capitals across the UK.
It will be open to the public and those planning to attend are encouraged to bring a candle. The ceremony will include a short act of remembrance and wreath laying, with “lights out” in City Hall for a period during the vigil.
For other Lights Out events visit: http://www.1418now.org.uk/lights-out/