King Charles III, who's in Italy with his wife Queen Camilla, became the first British monarch to address a joint session of the Parliament in Rome on Wednesday.
The 76-year-old drew warm applause from lawmakers by showing off his language skills during his historic speech, switching between English and Italian.
In his speech, the monarch underlined the importance of strong ties between Italy and Britain.
The King's speech comes amid Harry's legal battle for his security protection with Home office in the UK.
The King states: "Peace is never to be taken for granted."
He continued: "Britain and Italy stand today united in defence of the democratic values we share. Our countries have both stood by Ukraine in her hour of need, and welcomed many thousands of Ukrainians requiring shelter."
The king praised Anglo-Italian plans to develop with Japan a new fighter jet as part of the Global Combat Air Programme initiative.
Britain quit the European Union in 2020 and the royal visit is seen as part of an ongoing effort by London to engage with its old EU allies and ease the pain of the Brexit divorce.
The King delivered the concluding remark in English, declaring: "It is a signal honour to have been asked to speak to you all this afternoon."
Prince William and Harry's father said: "The first time that a British sovereign has addressed the entire Italian Parliament, this fundamental democratic institution."
The singer welcomed her son Sky with boyfriend Chanan Safir Colman in May 2023
King Charles' office releases statement after Prince William performs key duty
Dorit Kemsley files for divorce from Paul Kemsley after 10 years of marriage
Travis Kelce and Taylor Swift have been enjoying each other’s company away from the public eye
Tom Hardy shares unfiltered thoughts on 'Pride & Prejudice' audition rumours
Prince William, Kate Middleton's wedding list included their exes
