Obamas at Buckingham Palace gala

Britain's Queen Elizabeth II welcomes US president Barack Obama to a state banquet at Buckingham Palace in London on the first day of the Obamas' state visit.

Britain's Queen Elizabeth II welcomes US president Barack Obama to a state banquet at Buckingham Palace in London on the first day of the Obamas' state visit.

Queen Elizabeth II, US President Barack Obama, first lady Michelle Obama (behind her husband) and Prince Philip arrive at Buckingham Palace for the state banquet on the first day of the Obamas' state visit.

America's first lady Michelle Obama and Britain's Prince Philip arrive at Buckingham Palace in London for state banquet on the first day of the Obamas' state visit.

Queen Elizabeth II, US president Barack Obama, first lady Michelle Obama and Prince Philip at a state banquet at Buckingham Palace.

US president Barack Obama replies to Queen Elizabeth II's toast as the Quenn, Prince Philip (right) and Duchess of Cornwall (left) look on, at a state banquet at Buckingham Palace in London, on the first day of the Obamas' a state visit.

Britain's Queen Elizabeth II and US president Barack Obama toast each other during a state banquet at Buckingham Palace in London, on the first day of the Obamas' state visit. Not that although Obama and Prince Phillip (to the Queen's right) are drinking white wine, the Queen's glass is filled with water.

Queen Elizabeth II and US president Barack Obama chat during a state banquet at Buckingham Palace in London, on the first day of the Obamas' state visit.

Queen Elizabeth II welcomes US president Barack Obama to a state banquet at Buckingham Palace on the first day of the Obamas' state visit.