Prime Minister Boris Johnson and US President Joe Biden met on Thursday and agreed to "further enhance the world's strongest bilateral defence, security and intelligence partnership", the Ministry of Defence (MOD) said.
Both the UK and the US will work towards increasing NATO's common funding and strengthening and modernising the Alliance towards emerging threats, including cyber attacks.
Defence Secretary Ben Wallace said it is "no secret that the US is our closest friend and most important defence partner".
"Combining the largest defence budget in the world and the largest defence budget in Europe, the US-UK alliance is a bulwark against those that aim to undermine the rules-based international order," the UK Defence Secretary said.
The Joint Statement also remarks that the commitment the UK and the US share to ensure that space is a "safe and secure environment for all", the MOD said.
Steps agreed by both the US President and the Prime Minister also look at tackling "illicit finance and corruption", as well as terrorism.
Home Secretary Priti Patel said the UK-US co-operation will enable the United Kingdom to "better combat terrorism, tackle illicit finance, dismantle the serious and organised crime groups who operate across our borders, and go after the individuals who prey on the most vulnerable in society, including our children".
The UK and the US have been long-standing defence allies and most recently, said co-operation between countries is being demonstrated by the role US forces are placing alongside the Carrier Strike Group 21 (CGS21) as ships, aircraft and personnel set sail on a seven-month operational deployment around the globe, spearheaded by the Royal Navy's aircraft carrier HMS Queen Elizabeth.
Cover image: US President Joe Biden and UK Prime Minister Boris Johnson pictured ahead of the G7 meeting in Cornwall (Picture: PA/Alamy).