The UK has agreed to double imports of US gas over the next year as it tries to stabilise soaring energy prices.
Prime Minister Rishi Sunak said the plan would "bring down prices for British consumers and help end Europe's dependence on Russian energy".
The UK does not import gas from Russia directly, but has been hit by rising wholesale prices on the Continent.
Under the agreement, the UK aims to double imports of liquefied natural gas (LNG) from the US to 9-10 billion cubic metres over the next year.
That is equivalent to about an eighth of the gas the UK uses every year.
The two countries will also boost collaboration over the development of new nuclear and green energy technologies.
The partnership will be steered by a new UK-US joint action group, led by senior officials from the British government and the White House, with the first meeting held virtually on Thursday.