Barack Obama has sent the Queen the "heartfelt congratulations of the American people" to mark her Diamond Jubilee.
The US President paid tribute to her 60 years on the throne, saying that although presidents and prime ministers have come and gone, her "reign has endured".
In a video message posted on the White House website, he said the Queen was a living witness to the power of the alliance between the two nations.
"In war and in peace, in times of plenty and in times of hardship the United States and the United Kingdom have shared a special relationship," he said.
"We have stood tall and strong and faced some of the greatest challenges this world has known.
"While many presidents and prime ministers have come and gone, your majesty's reign has endured."
The US president's father, also Barack Obama, was born in Kenya when it was part of the British Empire, before moving to the United States and beginning a degree in business administration in autumn 1959, aged 23.
Mr Obama senior met a white American called Ann Dunham on a Russian language course at the University of Hawaii in 1960. The following year they married and had a son, who went on to be elected the first black US president in 2008.
In a message to the the Queen, the British people and members of the Commonwealth, Mr Obama said she was "a chief source" of the resilience of the links between his country and the UK and called her 60-year reign "extraordinary".
"As a steadfast ally, loyal friend and tireless leader, your majesty has set an example of resolve that will be long celebrated," he said.