"We are thrilled to be here," President Barack Obama said as he greeted Ireland's president Mary McAleese on Monday.
Despite the grey skies looming over the Emerald Isle, the 49-year-old added: "The sun's coming out – I can feel it.".
First Lady Michelle Obama accompanied her husband for the trip to Ireland which has seen him return to his ancestral home - which had been decorated with American flags for his visit.
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Barack visited Moneygall, a village of 300 residents, where one of his mother's ancestors was born before emigrating to America in 1850.
The excitement was tangible, and he was welcomed with whoops of delight from over 3,000 people who had lined the streets of the tiny village.
The first couple did not disappoint as they embarked upon a long walkabout, wowing the assembled masses by making sure to greet as many of the revellers as possible.
He also met a distant cousin, whom he greeted with a big hug.
They then visited the local pub, Hayes, which is full of Barack Obama memorabilia, including a life-size bust which has pride of place on the bar.
The famous couple were unable to avoid the rain, which may have dampened their clothing but not their spirits, and they set about greeting local dignitaries in the pub and then sipped on pints of Guinness.
Earlier in the day, he held private talks in the drawing room of the Aras with the Irish Prime Minister, Taoiseach Enda Kenny, before posing with a hurling stick he received as a present.
This seven-day trip will also see the couple visit England, Poland and France.