Former US president Barack Obama popped into Downing Street on Monday for private talks with Rishi Sunak.
Mr Obama, who served in the White House from 2009 to 2017, smiled and waved at members of the press before he entered No 10 shortly after 3pm.
HIs visit was understood to be a courtesy call as he was in London.
Details of what he was due to discuss with Mr Sunak were not clear.
But the Ukraine war could be one issue they discuss given the threat posed by Vladimir Putin to Europe.
Mr Obama angered some Tories when he warned during the 2016 referendum campaign on Brexit that Britain would be at the “back of the queue” for a free trade deal if it splintered away from the European Union.
But the then president has proved right with still no sign of a free trade deal between the UK and America, despite leading Brexiteers having argued that such a pact would be easy.
Mr Obama’s visit caused an immediate stir in Westminster.
But it was far less surprising than when Bill Clinton, the year after he had left the White House, turned up at Labour’s annual rally in Blackpool in 2002 and popped into the local McDonald’s restaurant.
Local people going in to buy a burger or other food were stunned to see the former US president there.
Mr Clinton posed with staff, as he enjoyed a drink.
He delivered a barn-storming speech at Labour’s annual conference that year, around half way through Tony Blair’s New Labour premiership.
