South Korean President Moon Jae-in is to visit the North Korean capital Pyongyang next month to meet the North's leader, Kim Jong-un.
It will be the first time in more than a decade that a South Korean leader has visited Pyongyang and it comes after cultural and sporting exchanges.
Mr Moon has already met Mr Kim twice this year for summits.
An adviser said the South was trying to persuade the North to take concrete steps towards nuclear disarmament.
"Our government is trying to play role of facilitator," said Chung-in Moon, special adviser to President Moon.
The two Koreas have developed their relationship since the new year after Mr Kim promised to suspend nuclear missile tests.
This rapprochement helped lead to a summit between Mr Kim and US President Donald Trump in June, and an agreement to denuclearise the Korean peninsula.
However, there has yet to be a breakthrough on that goal.
The North has accused Washington of making gangster-like demands for denuclearisation and criticised South Korea for taking part in US-led sanctions with "blind obedience".
When will President Moon go?
No date was given for the forthcoming summit, which was announced after talks at the border between the two states.
North Korean chief delegate Ri Son-gwon told reporters it would be fun to keep them guessing.
The two previous summits, in April and May, took place on the border at Panmunjom.
What is the US doing?
Chung-in Moon said he believed US Secretary of State Mike Pompeo would be visiting Pyongyang as early as next week.
"I think that Pyongyang and Washington will be able to produce some kind of compromise," he said.
"And we are hoping that Secretary Pompeo can work out some compromise with the North Korean counterpart. And also we have been telling North Koreans without making some concrete moves toward denuclearisation it will be very difficult for the US to accept the North Korean position."
Earlier this month, a report commissioned by the UN Security Council found that North Korea had not stopped its nuclear and missile programmes, thus violating UN sanctions.
It also said Pyongyang had resorted to a "massive increase" of illegal ship-to-ship transfers of oil products and had been trying to sell weapons abroad.