Fresh assembly elections in Northern Ireland are to be held on 26 November, Downing Street has confirmed.
David Trimble and Gerry Adams have concluded their negotiations
The announcement was made on Tuesday after weeks of top-level negotiations between Sinn Fein and the Ulster Unionists, as well as the British and Irish Governments.
Northern Ireland's devolved administration was suspended a year ago amid allegations of IRA intelligence-gathering in the Stormont government.
Assembly elections were postponed in May over what the government called a lack of clarity about the IRA's future intentions.
A deal now reached is believed to include a third act of decommissioning by the IRA.
The confirmation of the assembly election date is the first step in a complex sequence of developments set to unfold on Tuesday.
Reacting to the news of an election date, Michael McGimpsey of the UUP said within hours, unionists may know what republican intentions are about the future of the IRA.
"Republicans must convince people that they are committed to peace and to the process and to democracy."
The SDLP's Alex Attwood said people would have one standard against which to judge Tuesday's events.
"That is, will those who have had problems in the past, have resolved those problems and step up to all the requirements of the Good Friday Agreement, ending paramilitarism, endorsing policing, and working all-Ireland bodies."
Sinn Fein's Alex Maskey welcomed the announcement.
"I look forward now to having elections," he told BBC Radio 4's Today
Nigel Dodds of the Democratic Unionist Party also welcomed the announcement.
"I think it was, quite frankly, anti-democratic and outrageous that the election should have been postponed twice already," he said.
Later on Tuesday, Sinn Fein President Gerry Adams is expected to make a keynote speech dealing with the future of IRA activity.
Northern Ireland decommissioning head General John de Chastelain is then due to outline details about what is understood to be a major act of IRA disarmament.
After this, an IRA statement is to be released, underlining republican intentions.
Ulster Unionist leader David Trimble will provide his initial response, probably confirming that he intends to bring any deal to his party's ruling council.
There is a growing expectation the British and Irish Prime Ministers, Tony Blair and Bertie Ahern, could arrive in Northern Ireland on Tuesday to give their approval to the deal.