King Charles has voiced strong support for the AUKUS pact, warning against the 'forces of tyranny,' during a State Banquet at Windsor Castle for US President Donald Trump and First Lady Melania Trump.
The lavish dinner on Wednesday night was hosted by the King, joined by around 160 royals, dignitaries and celebrities.
He praised the 'innovative' AUKUS submarine agreement with Australia and highlighted the deep historical bond between the UK and the US.
'Our countries have the closest defence, security and intelligence relationship ever known,' he said.
'In two world wars, we fought together to defeat the forces of tyranny.
'Our people have fought and died together for the values we hold dear.
'We have celebrated together, mourned together and stood together in the best and worst of times.
'Today, as tyranny once again threatens Europe, we and our allies stand together in support of Ukraine to deter aggression and secure peace, and our AUKUS submarine partnership with Australia sets the benchmark for innovative and vital collaboration.'
US President Donald Trump was feted with a State Banquet at Windsor Castle during a second state visit.
Australia's AUKUS pact was given a mention in King Charles' speech, as the King praised the nations' mutual assistance and 'innovative' deal.
King Charles also praised the President's 'personal commitment to finding solutions to some of the world's most intractable conflicts.'
He joked about the longtime allies' close relationship, referencing his 1970 visit to the US and being photographed with former President Nixon's daughter, Tricia.
'Had the media succeeded in the1970s in their own attempt at deepening the special relationship, I myself might have been married off within the Nixon family,' he said to laughter in the room.
King Charles concluded his speech by highlighting the two leaders' 'unshakeable trust.'
'The bond between our two nations is indeed a remarkable one. Forged in the fire of conflict, it has been fortified through our shared endeavours and burnished by the deep affection between our people,' the King said.
'In renewing our bond tonight, we do so with unshakeable trust in our friendship and in our shared commitment to independence and liberty,' he added before proposing a toast.
'As we celebrate this unparalleled partnership, allow me to propose a toast - to President Trump and the First Lady, and to the health, prosperity and happiness of the people of the United States of America.'
Anthony Albanese could meet Trump later this month on the sidelines of the United Nations General Assembly meeting, where discussing the future of AUKUS is likely to be high on the agenda.