THE historic handshake planned between the Queen and Martin McGuinness is to take place behind closed doors, it emerged tonight.
The Northern Ireland Deputy First Minister will attend a cross-border event in Belfast on Wednesday, which Irish President Michael D Higgins will also attend.
But the initial meeting and handshake between the Queen and the senior Sinn Fein representative is expected to take place in a private room at the beginning of the engagement, sources close to the planning have said.
The meeting is nevertheless being seen as a major milestone in efforts to normalise relations between nationalists and unionists.
Sinn Fein president Gerry Adams confirmed that his party's ruling executive had backed the planned meeting.
But he added: "This will understandably cause difficulties for some republicans and nationalists, especially for those folks who suffered at the hands of British forces."
Mr Adams said Sinn Fein wanted to see a new republic in which the traditions of orange and green could be brought together in a cordial union.
The ard comhairle decision was not unanimous but was a clear majority, the party confirmed.
Leading cross border charity Co-operation Ireland is to host the event for the Queen and President Higgins to celebrate the arts and culture across the island.
There has been speculation since the Queen's momentous visit to Ireland in May last year that a senior Sinn Fein figure would meet her at an event.
Mr McGuinness, a former IRA commander, was always the candidate to shake the Queen's hand but delicate talks have been going on for months to arrange a suitable venue and occasion.
Sinn Fein have stressed the meeting is not a celebration of the Jubilee.
Mr Adams defended the decision, saying: "We don't have to do it. We're doing it because it's the right thing to do, despite the fact that it will cause difficulties for our own folk.
"But it's good for Ireland. It's good for this process we're trying to develop. It's the right time and the right reason.
"After Martin McGuinness completes this engagement he will be as true, as staunch, as active a republican as he ever was."
The Northern Ireland Deputy First Minister, a chief negotiator for Sinn Fein during tough talks to bring the IRA terror campaign to an end, turned down an invitation to meet the Queen during her visit to Ireland last year.
During her trip, the Queen won over many people by paying her respects to Ireland's patriot dead at the Garden of Remembrance in Dublin, among many other significant engagements.
Irish Taoiseach Enda Kenny, in Scotland at the British-Irish Council summit today, said he had been confident the handshake would be agreed to.
"It's not the first time that the Sinn Feiner has met a member of royalty," Mr Kenny said.
"The Queen herself, when she spoke in Dublin Castle, said in hindsight if we could do things again there are some things that we might do differently, and some things that we wouldn't do at all.
"We're in a very different space in 2012. We're in a modern era."
Mr Kenny also said that a refusal to shake hands would have been a very retrograde step.
Mr Adams called for support for the meeting and handshake from republicans and nationalists and said it was a "symbolic and significant step".
He urged people opposed to the move to protest peacefully.
It had been believed that plans for a 20,000-strong Diamond Jubilee celebration, to be held at Stormont during the Queen's two-day visit, made it more difficult for republicans to hold the meeting there.
But an engagement involving not only the Queen but also Ireland's head of state provides a more acceptable backdrop for Sinn Fein.
It is understood to be taking place in the Lyric Theatre in south Belfast and is sponsored by Co-operation Ireland which works to bring divided communities together.
Since it was established in 1979, the charity has created opportunities for groups from the two main religious communities in Northern Ireland and from both sides of the border to learn about each other's traditions and cultural backgrounds in order to help build a society based on tolerance and acceptance of cultural difference.
The handshake will be viewed as another in a long list of dramatic advances in Anglo-Irish relations.
One of the most significant was the Queen laying a wreath at the Garden of Remembrance in Dublin - a duty on every official State visit to the Republic - followed by a tour of the headquarters of the Gaelic Athletic Association (GAA) before she spoke Irish at a banquet in her honour, which Mr McGuinness had snubbed.
Since those events the Deputy First Minister has spoken several times of how he was struck by the Queen's gestures at the time.
First Minister Peter Robinson, leader of the Democratic Unionist Party, has said republicans should pay due respect to the Queen as a recognition of her importance to many in Northern Ireland.
Mr McGuinness, who was also in Scotland today at the inter-governmental meeting, has said his party's decision would be guided on what would be best for the peace process.
Mr Robinson was among those who said such a meeting would also be difficult for the Queen, given that her own family was hurt by republican violence when the IRA killed Lord Mountbatten in a 1979 bombing in Co Sligo.