From discussing nuclear war to belting out a beloved hit, South Korean President Yoon Suk Yeol's White House visit ended on a high note when he sang Don McLean's "American Pie" to great applause.

Yoon is on a six-day state visit to Washington, where he discussed with US President Joe Biden on Wednesday "the end" of any North Korean regime that used nuclear weapons against the allies.

But the two leaders had more cheerful topics on the agenda at the White House state dinner in Yoon's honour later that day, with the South Korean leader – who is known at home to be something of a karaoke buff – sharing his love of American music.

"We know this is one of your favorite songs, 'American Pie,'" Biden said to Yoon, having pulled him up onto the stage at the end of the evening to listen to singers perform the classic.

"Yes, that's true," the 62-year-old Yoon admitted, saying that he had loved the Don McLean song, released in 1971, since he was at school.

"We want to hear you sing it," said Biden.

"It's been a while but..." Yoon responded, offering only token resistance as he took the microphone.

Yoon belted out the first few lines of the song a capella, triggering rapturous applause from the crowd and delighting Biden and the First Lady.

"The next state dinner we're going to have, you're looking at the entertainment," Biden told the crowd, referring to Yoon.

Then he turned to the South Korean president and said: "I had no damn idea you could sing."

Speaking at the White House after Oval Office talks during only the second state visit so far in the Biden presidency, the two leaders said the US security shield for South Korea was being strengthened in the face of the nuclear-armed North's aggressive missile tests.

And they made clear that if the isolated dictatorship in North Korea attacks the South or the United States, the response will be devastating. (AFP)