A State banquet in honour of President Michael D Higgins and his wife Sabina has begun at Windsor Castle.
Some 160 people are attending the dinner in St George's Hall, hosted by Queen Elizabeth as part of the four-day State visit.
The guests include the Taoiseach Enda Kenny, former President Mary McAleese and Sinn Féin's Northern Ireland Deputy First Minister Martin McGuinness.
The President and the Queen will both be making speeches.
Earlier today, President Higgins received a ceremonial welcome in Windsor, before addressing the Houses of Parliament in Westminster.
The Queen will sit to the left of President Higgins and the Duchess of Cornwall will sit on his right hand side.
British Prime Minister David Cameron and his wife Samantha, Deputy Prime Minister Nick Clegg and Labour leader Ed Miliband are also in attendance, with the First Minister of Northern Ireland Peter Robinson, Taoiseach Enda Kenny and Northern Ireland Secretary Theresa Villiers.
To start, the guests will dine on fillet of Isle of Gigha halibut with young leeks and fine herb sauce.
For the main course they will eat tornadoes of Windsor estate beef with wild mushrooms and water cress puree, served with purple sprouting broccoli and sauce hollandaise, baked onions stuffed with parmesan and bulghar wheat
For dessert guests will have vanilla ice-cream bombe with Balmoral redcurrant centre.
The tables are decorated with candelabras and flowers and foliage – including Bells of Ireland, a green flower – with shades of orange and white to represent the Irish colours.
Guests will be entertained by an orchestra.
Other members of the royal family at the banquet include the Prince of Wales who is sitting next to President Higgins’ wife Sabina, and the Duke of Edinburgh is sitting on her other side.
Former President Mary McAleese is also at the banquet.
President Higgins was given a pair of photographs of the Queen and the Duke, as well as a copy of Dubliners by James Joyce, which had been specially bound and boxed by the Windsor bindery.
Mrs Higgins was given a small silver engine-turned box with gold cypher, by William & Son.