Obamas to dine with Queen Elizabeth II, Prince William and wife Kate

London: Britain's Royals will this week host US President Barack Obama and First Lady Michelle at two separate events, during which the Obamas will dine with the Queen and the younger royals Prince William and wife Kate.

Obama and Michelle will attend a private lunch hosted by Queen Elizabeth II at Windsor Castle on Friday, a day after her 90th birthday on April 21, before joining William and Kate for an informal dinner at their home in London the same day.

"Their Royal Highnesses are very much looking forward to welcoming President and Mrs Obama to Kensington Palace," a Kensington Palace spokesperson said.

William, the Duke of Cambridge, last met Obama in the Oval Office in 2014 and extended a personal invitation to him. The Obamas had met the Queen and Prince Philip during their state visit to the UK in 2011.

Michelle is believed to have struck a close association with the British monarch since she ignored protocol to put her arm around the Queen during an official visit in 2009.

Obama will arrive in London on the evening of the Queen's birthday on Thursday and leave on Sunday.

The US President will be in the UK as part of a tour of Saudi Arabia and Germany.

Obama is widely expected to deliver a strong anti-Brexit message during his stay. There is also speculation that the June 23 European Union (EU) referendum could come up during his conversations with the Queen.

The referendum is to decide on Britain's possible exit from the European Union, dubbed 'Brexit.'

In Washington, White House Press Secretary Josh Earnest said the visit will allow President Obama to coordinate on today's most pressing international challenges with "one of our closest allies."