Nick Clegg has described the UK-US relationship as "built to last" as he prepared for White House talks with Vice President Joe Biden.
On his first visit to the US as Deputy Prime Minister, Mr Clegg also had a chance encounter with President Barack Obama at the United Nations in New York on Wednesday night.
He said they had discussed the UN Millennium Development Goals summit as they were preparing to address the General Assembly.
On Thursday he will be having lunch with Mr Biden after taking the train to Washington late on Wednesday night.
"It's all part of this terrifically important relationship between the United Kingdom and the United States," he told the BBC.
"It ebbs and flows over time but it is hugely important and it is built to last."
Mr Clegg said they would be discussing progress in Afghanistan and what needed to be done to achieve a "political solution" there over the next few years.
He dismissed suggestions that the US government was concerned about the coalition's deficit reduction strategy, saying each country had to respond to its own circumstances.