Sinn Féin’s Martin McGuinness has shaken hands with Queen Elizabeth in the Lyric Theatre in south Belfast this morning.
The pair first shook hands away from the media spotlight behind closed doors.
They met in a room within Belfast’s Lyric theatre during an event celebrating the arts in the Republic and Northern Ireland.
But later, as the queen left to continue her diamond jubilee tour of Northern Ireland, the pair shook hands again, this time in public.
As they shook hands for a second time, Mr McGuinness said "slán agus beannacht", telling the queen it meant "goodbye and Godspeed".
Also in attendance at the meeting was President Michael D Higgins, who with Queen Elizabeth is patron of Co-operation Ireland, organisers of the reception. The meeting, in a quiet space used by the Lyric for creative learning, was also attended by the Duke of Edinburgh, Northern Ireland first minister Peter Robinson and the President's wife Sabina Higgins.
It is understood that during the VIPs' initial private meeting, Mr McGuinness welcomed both the queen and President Higgins in Irish. Mr McGuinness is said to have commented briefly on the queen's visit to Dublin last year, and in particular her comments regarding all the victims of the conflict.
A Sinn Féin spokesman said: "He emphasised the need to acknowledge the pain of all victims of the conflict and their families."
Mr McGuinness is said to have spoken to the queen of the significance of her visit, and of the need for it to be built upon in the time ahead.
Sinn Féin said Mr McGuinness told the queen that their meeting was a "powerful signal that peace-building requires leadership".
He also praised the role of the President in today's encounter, and welcomed that the engagement took place at an event celebrating culture across Ireland.
In a statement this afternoon, President Higgins welcomed his "warm" meeting with Queen Elizabeth. "We recalled the very successful State visit to Ireland last year and its extremely positive impact on the wide spectrum of relations between Ireland and Britain," he said in statement. "I conveyed to Her Majesty my wish, during my term in office, to avail of all appropriate opportunities to build on that very encouraging template of enhanced British-Irish relationships.
"The exchange of greetings and courtesies that took place this morning marks another important step on the journey to reconciliation on this island. I believe this will be very helpful in the continued realisation of the full potential of the Good Friday Agreement and in improving relationships between all communities who share this island."
Mr McGuinness is to speak at Westminster tomorrow night on what Sinn Féin has billed as a “keynote address on future British-Irish relations”.
About 50 guests, mostly representative of the Northern Ireland arts world, including the poet Michael Longley, pianist Barry Douglas, actors Adrian Dunbar and Conleth Hill, painter Colin Davidson and singer Brian Kennedy, attended this morning's reception.
“This event aims to highlight how the arts have contributed to reconciliation and peace-building on the island of Ireland,” said former senior PSNI officer Peter Sheridan, who is chief executive of Co-operation Ireland.
Following the event in the Lyric, the queen went to the Titanic Belfast visitor centre near where the famous liner was built. It tells the story of the vessel's construction, journey and North Atlantic sinking, in which more than 1,500 people died, in April 1912 on its maiden voyage from Southampton to New York.
She visited the Arrol Gantry gallery, the drawing offices where the Titanic was designed and an area overlooking the slipways where the liner was launched.
She also saw the fit out gallery depicting where the liner was prepared for sea and went on a virtual shipyard ride about the building of the vessel. The tour lasted about half an hour.
She was serenaded by members of the Belfast Community Gospel Choir and had lunch at the Titanic Suite. On the menu was Guinness and treacle bread, Glenarm salmon, chicken breast with sweet cure ham hock and glazed lemon curd tart.
The queen accepted a gift of a Belleek Pottery basket from Stormont enterprise minister Arlene Foster.
A few hours later, the queen waved to crowds from an open-topped car at a celebration of her diamond jubilee in Stormont attended by over 20,000 people - a stark contrast to the armoured limousines that have been a mandatory precaution on previous visits.
She has now returned to London.
Meanwhile, some unionist politicians have condemned the erection of a large sign on Black Mountain overlooking Belfast which has an Irish Tricolour underneath, and stating “Eriu is our Queen”, a reference to the mythological goddess of Ireland.
DUP North Belfast MP Nigel Dodds said the sign was indicative of a “small group of republicans [who] cannot respect the views of the vast majority of people in Northern Ireland”.