The King will meet with US President Joe Biden for tea and will be briefed on climate discussions on Monday.
Mr Biden arrived in London on Sunday night and will meet with the Prime Minister in the morning before he heads to Windsor Castle.
There Mr Biden will receive a royal salute, hear the US national anthem performed by the Welsh Guards and will then have a cup of tea with Charles.
They are to then meet with financial and philanthropic leaders who will have attended the climate finance mobilisation forum.
Charles and Mr Biden will then be briefed on the outcomes of the meeting, mainly around the support they can offer poorer countries.
It is the first time the pair have met since the coronation as First Lady Jill Biden was in attendance to represent the US.
Mr Biden was in attendance at the Heads of State Reception at Buckingham Palace on the eve of the late Queen’s funeral before he and Mrs Biden attended the funeral service in September last year.
They had previously met at the G7 Leaders Summit in June 2021 and Cop26 in Glasgow later that year.
They shared a handshake at Cop26 and Mr Biden expressed his like for Charles’ passion for combatting climate change and his environmental activism.
Mr Biden will meet Rishi Sunak in Downing Street earlier on Monday for discussions that could touch on cluster munitions and Ukraine’s bid to join Nato.
The White House said they will “compare notes” on the Ukrainian counter-offensive as it makes slow but steady progress in driving out the Russian forces.
The UK visit is a layover before Mr Biden heads to the Nato summit in Lithuania.
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