Kim is due to meet South Korean President Moon next month, followed by a landmark nuclear summit with US President Donald Trump, which could come as early as May.
The rapid rapprochement was kicked off by the Winter Olympics in the South and comes after a year of heightened tensions over the North's nuclear and missile programmes, which saw Kim and Trump engaging in a fiery war of words.
Events have since moved rapidly, with a flurry of official visits between the two Koreas before Kim went to Beijing this week to meet Chinese President Xi Jinping for the first time.
Three-member delegations from the two Koreas were to meet at the Unification Pavilion building on the northern side of the border truce of village of Panmunjom on Thursday to discuss the exact date and agenda of next month's summit.
Seoul's delegation was to be led by Unification Minister Cho Myoung-gyon, and Pyongyang's by his counterpart Ri Son Gwon, who is chairman of the North's Committee for the Peaceful Reunification of the Country.
Also Thursday, China's State Councillor Yang Jiechi, the country's top diplomat, was due in Seoul to brief Moon on Kim's secretive visit to Beijing.
It was the North Korean leader's his first overseas trip since inheriting power after the death of his father, Kim Jong Il, in 2011.
Even so the two leaders hailed their nations' historic relations, with Xi accepting Kim's invitation to Pyongyang according to the North's official Korean Central News Agency.
"There is no question that my first foreign visit would be to the Chinese capital," it quoted him as saying, calling it a "noble obligation".
Kim pledged that he was "committed to denuclearisation" on the Korean peninsula, according to China's Xinhua news agency -- but added that it was dependent on South Korea and the US taking what he called "progressive and synchronous measures for the realisation of peace".
Analysts say that both sides had reasons for the meeting -- Pyongyang to secure Beijing's backing and support, and China to protect its interests in what it considers its backyard.
Robert Kelly, a professor at Pusan National University in South Korea, said: "Xi would not grant this meeting unless the Chinese were genuinely concerned about the summits to come and wanted some kind of role to play."
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