Chancellor Gordon Brown has had private talks with US President George W Bush, American officials have confirmed.
It was the first time Mr Brown and Mr Bush had met each other
In their first face-to-face meeting, the two men spent 45 minutes at the White House discussing Afghanistan and Iraq, as well as trade liberalisation.
It is thought the meeting was unplanned and was suggested by Mr Bush, who knew the chancellor was at the White House talking to national security officials.
Mr Brown is in Washington for meetings at the International Monetary Fund.
The BBC's Robin Brant said the meeting was the "strongest sign yet" of preparations being made on both sides of the Atlantic for the prospect of Mr Brown representing the UK on the international stage as prime minister.
Our correspondent said the impromptu sit-down also showed that Gordon Brown knows which relationship is most important for British foreign policy.
Sources close to the chancellor told the BBC the meeting with the president was completely unplanned.
Mr Brown was in a scheduled meeting with US national security adviser Stephen Hadley when President Bush appeared and said they should talk.
The two men had previously never met face-to-face.