The Queen wore green as she arrived in Dublin for the start of an historic four-day visit amid the tightest security ever mounted in the Irish Republic.
The sovereign chose the colour in the first symbolic gesture of what will be an unprecedented and dramatic stay in the state - the first by a British monarch.
She wore a jade green coat and hat as she emerged from a flight which touched down on time at Baldonnel aerodrome ahead of an official greeting by Irish President Mary McAleese at her residence in Phoenix Park, Aras an Uachtarain.
On official trips the Queen often compliments host nations by incorporating national colours or emblems.
The monarch, accompanied by the Duke of Edinburgh, was escorted down the red carpet at Baldonnel to a motorcade, past an Irish Air Corps guard of honour to accept flowers from eight-year-old Rachel Fox, from Dun Laoghaire, south Dublin.
At the gates leading to the Aras the Irish Tricolour and Union flag flew side by side.
The Queen's escort to the Aras included 33 green Honda motorbikes with green, red and black tricolour flags of the Second Cavalry Squadron, representing the 32 counties of Ireland, plus one with the Union flag.
The Queen shook hands with the President at the front of the Aras before moving inside to be greeted by Ireland's Taoiseach Enda Kenny and sign the visitors' book.
One of the monarch's first official engagements will be a wreath-laying ceremony at the Garden of Remembrance in Dublin city centre which honours all those who fought for Irish freedom from British rule.
Security concerns were highlighted after a pipe bomb was discovered in the luggage compartment of a bus which was on its way to Dublin on Monday night.