A service of reflection is due to get under way around now for Britain's Queen Elizabeth in Belfast.
President Michael D Higgins, Taoiseach Micheal Martin and Foreign Affairs Minister, Simon Coveney, are attending the event at St Anne's Cathedral.
Britain's King Charles is visiting Northern Ireland for the first time in his new role.
Earlier, he met political leaders at Hillsborough Castle in County Down and told the gathering of the Queen's affection for the people of the North.
