Foreign Secretary Boris Johnson has met senior members of President-elect Donald Trump's team during a trip to New York.
Mr Johnson met Mr Trump's son-in-law Jared Kushner and his chief strategist Steve Bannon.
He will also meet key Republican figures in Washington DC, including House Speaker Paul Ryan and senators Bob Corker and Mitch McConnell.
The subject of the talks has not been publicly revealed but the Foreign Office said the visit followed a successful meeting last month between the Prime Minister Theresa May's chiefs of staff and Mr Trump's team.
A Foreign Office spokesman said: "The discussions will be focused on UK-US relations and other foreign policy matters."
Mr Johnson has been critical of Mr Trump in the past, including his response to the billionaire's description of parts of London as a no-go area for police.
Mr Johnson had replied: "The only reason I wouldn't go to some parts of New York is the real risk of meeting Donald Trump."
The meeting comes after Mrs May condemned Mr Trump's comments about groping women as "unacceptable" but voiced hopes that the relationship between the two countries could flourish during his presidency.
Speaking on Sky News, Mrs May said: "I think (the comments about groping women were) unacceptable but, in fact, Donald Trump himself has said that and has apologised for it.
She told Sophy Ridge on Sunday: "But the relationship that the UK has with the United States is about something much bigger than just the relationship between the two individuals as president and prime minister.
"That's important, but actually we have a long-standing special relationship with the United States.
"It's based on shared values and it is a relationship where, actually in the UK, we feel we can say to the US if we disagree with something that they are doing."
Mr Trump has tweeted he was "very much" looking forward to meeting the PM, adding that he considered Britain to be a "very special" ally - a signal the "special relationship" between the US and the UK will be maintained under his administration.
He and Mrs May are due to meet in Washington in the spring after the PM's closest advisers travelled to the US in December to forge links with the President-elect's team and pave the way for the visit.