PRESIDENT GEORGE W Bush visits Stormont today on the final leg of his European tour to honour a long-standing commitment to the heads of the Northern Ireland Executive.
The Taoiseach will also meet the president and British prime minister Gordon Brown in Belfast.
Last December during their talks at the White House Mr Bush made clear to Dr Ian Paisley, then First Minister, and to Martin McGuinness he was anxious to show his personal support for the Stormont institutions which were restored last year.
The president had hoped to visit Belfast during last month's US-Northern Ireland investment conference but had to reschedule his plans. He sent his best wishes by video message instead.
Following his arrival at Belfast International Airport from London, Mr Bush will be welcomed at Stormont Castle by the new First Minister Peter Robinson and by Mr McGuinness, the Deputy First Minister.
Mr Brown meets Mr Bush for talks in London this morning and will rejoin him at Stormont.
Taoiseach Brian Cowen will attend the meeting at Stormont Castle where he is also expected to have an informal discussion on the rejection of the Lisbon Treaty with the British prime minister.
He will not be accompanied by Minister for Foreign Affairs Micheál Martin who will be in Luxembourg for talks with EU foreign ministers.
Mr Bush will not visit Parliament Buildings even though the normal plenary sitting of the Assembly has been postponed and no committee meetings are to be held.
This decision has been criticised as needless by the Alliance Party.
First lady Laura Bush will accompany her husband on the visit to Belfast.
She was not with him on his first trip to Northern Ireland in April 2003 when he and the then prime minister Tony Blair held a summit on the Iraq war at Hillsborough Castle.
That visit also included talks with the then taoiseach Bertie Ahern and short meetings with delegations from the pro-Belfast Agreement parties.
Stringent security measures were put in place over the weekend.
Airspace over Belfast is strictly controlled and a no-fly zone for helicopters has been established.
There were warnings of significant traffic restrictions in the vicinity of the Stormont estate in the east of the city and at two other locations in the greater Belfast area to be visited separately by the president and Mrs Bush.
Stormont itself will be sealed off this morning, with elected representatives, civil servants and the press required to stay on-site for five hours until the presidential party departs for the US late this afternoon. A number of protests are anticipated and the PSNI has been notified of demonstrations outside Stormont and at Belfast City Hall.
Mr McGuinness is expected to raise with Mr Bush questions about US foreign policy and a protest is being mounted by Ógra Shinn Féin.
"We will be mobilising our activists to send a message loud and clear that the occupations of Iraq and Afghanistan are illegal and must come to an end," said organiser Barry McColgan.
Amnesty International has written to Mr Robinson and Mr McGuinness calling on them to raise the issues of Guantanamo Bay, torture and extraordinary rendition when they meet the president.
In the letter, Amnesty's Northern Ireland director Patrick Corrigan urges the First and Deputy First Ministers to use the opportunity of the Bush visit to call for a closure of the Guantanamo camp and disclose detailed information about the use of Shannon airport for "extraordinary rendition" flights.
Yesterday Amnesty staged a demonstration in Belfast in which about 40 protesters, dressed as Guantanamo detainees took part. Other activists, depicting Mr Bush tore up "copies" of the Geneva Conventions.