The King has met Ukrainian President Volodymyr Zelensky for the first time in a “truly special” audience at Buckingham Palace.
Mr Zelensky was dressed in his trademark khaki green military fatigues as he was welcomed to the royal residence on Wednesday afternoon.
Charles greeted the president with wide smile and a warm handshake in the Palace’s 1844 Room.
The president is on his first visit to the UK since the Russian invasion of his country began and in his address to Parliament said he would take the opportunity to thank Charles for the support he had shown Ukraine as the Prince of Wales.
He said meeting the King was a “truly special moment” and referred to Charles’s former military service in the Royal Air Force, saying: “The King is an air force pilot and in Ukraine today, every air force pilot is a king.”
Mr Zelensky told a packed Westminster Hall in an impassioned speech: “Today I will have the honour to be received by His Majesty the King.
“It will be a truly special moment for me, for our country.
“In particular because I will convey to him from all the Ukrainians the words of gratitude for the support His Majesty showed to them when he was still the Prince of Wales.
“I also intend to tell him something I think that is very, very, very important, not only for the future of Ukraine but for the future of Europe
“In Britain, the King is an air force pilot and in Ukraine today, every air force pilot is a king.”
He finished with “God bless Great Britain and long live the King.”
In May 2022, Charles, then the Prince of Wales, spoke out about the “nightmare situation” in Ukraine during a trip to Romania to meet refugees who have fled the war in their homeland.
Speaking through an interpreter, the prince told a group of Ukrainian families: “We feel for Ukraine, a nightmare situation. Keep praying.”
In March last year, Charles said the values of democracy were under attack in Ukraine in the “most unconscionable way”.
“In the stand we take here, we are in solidarity with all those who are resisting brutal aggression,” he said.
Charles has been outspoken in the past about Russian president Vladimir Putin and his annexation of the Ukrainian peninsula of Crimea.
He sparked a diplomatic storm in 2014 when he compared Mr Putin to Hitler during a visit to Canada.
He was speaking to Canadian museum volunteer Marianne Ferguson, who told him how her Jewish family fled the Nazi occupation of Danzig at the outset of the Second World War, when he drew a parallel with Russia’s annexation of Crimea.
Mr Putin, in a direct message to Charles, publicly branded the comments “unacceptable” and said such remarks were “not what monarchs do”.
As he arrived at the Palace, Mr Zelensky was driven through the gate and across the forecourt into the quadrangle.
He was greeted at the King’s Door firstly by the King’s equerry, Lieutenant Colonel Jonny Thompson.
Lt Col Thompson, dressed in his military uniform with kilt, shook hands with Mr Zelensky before introducing him to Sir Clive Alderton, principal private secretary to the King and Queen Consort.
Sir Clive also shook hands with the president before welcoming him inside Buckingham Palace.
The meeting was scheduled to last for 45 minutes.