Queen Elizabeth Obama
Queen Elizabeth II and US President Barack Obama during a State Banquet in Buckingham Palace (Reuters)

President Barack Obama will have a private lunch with the Queen at Windsor Castle next month during what will be his final visit to Britain as US President. Obama is expected to arrive just after the Queen celebrates her 90th birthday on 21 April.

The US President will be visiting the UK to hold a joint press conference with David Cameron at 10 Downing Street to encourage the British public to vote to remain inside the EU ahead of the historic referendum on 23 June.

Obama has said that the UK's EU membership gave the US "much greater confidence about the strength of the transatlantic union".

In a statement, a White House spokesman said: "The visit will allow the president to offer his gratitude to the British government and people for their stalwart partnership with his administration and the American people throughout his presidency."

Obama previously visited Buckingham Palace along with his wife, Michelle Obama, during a state visit in 2011 when the First Lady went against protocol by putting her arm around the monarch's waist.

After visiting the UK, Obama will continue his foreign tour, travelling to Germany to meet Chancellor Angela Merkel and attend Hannover Messe, the world's largest trade show for industrial technology. He will then head to Saudi Arabia on 21 April for a summit of the Gulf Cooperation Council, which will discuss the fight against the Islamic State (Isis).