The King dropped some references to South Korean popular culture as he hosted the country's president at a state banquet at Buckingham Palace.
Listening to the King's banquet address were singers Jennie Kim, Jisoo Kim, Lisa Manobal and Rose Park from the K-pop band Blackpink, South Korea's biggest girl group who became the first Korean band to headline a major UK festival during the summer.
K-pop, short for Korean popular music, includes styles and genres from around the world, such as hip hop, rock and R&B, on top of its traditional Korean music roots.
The King praised the environmental credentials of Blackpink and highlighted South Korea's creativity and culture, from Gangnam Style, celebrated in the global hit by Korean rapper Psy, to the popular Netflix series Squid Game.
He told the guests: "I applaud Jennie, Jisoo, Lisa and Rose, better known collectively as Blackpink, for their role in bringing the message of environmental sustainability to a global audience as ambassadors for the UK's presidency of COP26, and later as advocates for the UN sustainable development goals.
"I can only admire how they can prioritise these vital issues, as well as being global superstars. Sadly, when I was in Seoul all those years ago, I am not sure I developed much of what might be called the Gangnam Style."
In his banquet speech, the King also said "Koreans have created a miracle" in their journey from "wartime devastation" to a thriving country where the "industrial efficiency" he witnessed during a visit in 1992 had become the "epitome" of technological innovation.
He added: "Through their own sweat and toil, and under the shadow of tyranny and the ever present threat of aggression, over seven decades Koreans have built a bastion of democracy, human rights and freedom.
"In a world where these values are challenged, sadly, as rarely before in our lifetimes, the Republic of Korea and the United Kingdom stand shoulder to shoulder in defence of all that we hold dear."
The Queen and the Prince and Princess of Wales were also in attendance along with the Princess Royal, while Prime Minister Rishi Sunak and wife Akshata Murty were also guests.
During the white-tie banquet the guests dined on a menu of warm tartlet of soft poached egg and spinach puree, breast of Windsor pheasant with croquette of celeriac and calvados sauce and salad, with a mango ice cream bombe for dessert.
In his speech Mr Yoon echoed the sentiment of the King, praising the close ties between the UK and South Korea, saying: "When I was young, my friends and I were all fans of The Beatles, Queen, and Elton John. Harry Potter books are adored by many Koreans.
"Most importantly, the United Kingdom is the architect of modern liberal democracy. Most democracies are deeply influenced by British parliamentary democracy. Korea is no exception."
Alongside the pomp and pageantry, the UK and South Korea are to launch talks on a new trade deal and sign a diplomatic accord as part of Mr Yoon's three-day state visit.