President Barack Obama will meet Labour leader Jeremy Corbyn on Saturday, the White House said.
The meeting is expected to be closed to the media.
Mr Corbyn has been an outspoken critic of President Obama's foreign policy, once referring to him as a "Pentagon president like all the others".
President Obama and the First Lady have been welcomed by the Duke of Duchess of Cambridge and Prince Harry at Kensington Palace, where they will have dinner this evening.
US President Barack Obama has arrived at Windsor Castle to have lunch with the Queen.
The Queen and Duke of Edinburgh will host a private lunch for the US President and his wife Michelle at Windsor Castle.
It is a post-birthday affair for the Queen, who turned 90 yesterday, so the Obamas are expected to come bearing a gift.
Leave campaigners "can't claim" they want a closer relationship with the US and then say that President Obama has "no right to speak" about the EU referendum, according to Labour MP Alan Johnson.
ITV News Deputy Political Editor Chris Ship tweeted:
US President Barack Obama has arrived in the UK for an official four-day visit which will see him meet the Queen for her birthday celebrations, have dinner with William and Kate, and try to persuade British voters not to leave the EU.
The President touched down aboard Air Force One at Stansted Airport shortly after 9.30pm this evening before transferring on to a private helicopter.
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