Kim Jong Un will meet US President Donald Trump in May to discuss the possible end to North Korea's nuclear missile testing.
Speaking at the White House, South Korea's national security Chung Eui-Yong confirmed the North Korean leader "expressed his eagerness" to meet the US president "as soon as possible".
"I told the president in our meeting, that North Korean leader Kim Jong Un said he's committed to denuclearisation," Mr Chung said.
"Kim pledged that North Korea will refrain from any further nuclear or missile tests.
"President Trump ... said he would meet Kim Jong Un by May," Chung said.
If it goes the ahead, it would be the first time a US president had met with the leader of North Korea.
Seoul has already publicised that North Korea offered talks with the United States on denuclearisation and normalising ties, a potential diplomatic opening after a year of escalating tensions over the North's nuclear and missile tests.
It comes just days after the South's leaders held landmark talks with Kim Jong Un.
President Trump said had spoken to South Korean President Moon Jae-in, but did not give more detail.
A senior administration official said the announcement would be made by South Korean National Security Advisor Chung Eui-yong at the White House, who will be joined by White House press secretary Sarah Sanders.
The South Korean official is currently visiting Washington to brief US allies about his talks with North Korean leader Kim Jong Un in Pyongyang.
South Korea announced Tuesday that the North had stated there was "no reason" to hold on to its nuclear weapons "if military threats towards the North are cleared and the security of its regime is guaranteed".
The North is open to "frank" talks with the United States on denuclearisation and would suspend missile and nuclear tests while dialogue was under way, Chung said after returning from a meeting in Pyongyang with Kim.
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Trump welcomed the offer as "very positive" and refused to rule out a historic meeting with Kim. "We have come a long way at least rhetorically with North Korea," Trump said.
However his Director of National Intelligence Dan Coats told Congress he was "quite skeptical" and Vice President Mike Pence said the US position towards North Korea would not change "until we see credible, verifiable, and concrete steps toward denuclearization."
In the past North Korea has indicated that security guarantees mean US forces leave the Korean peninsula and break a mutual defence treaty with the South.
Breakthrough or stalling?
Seoul had earlier announced the two Koreas would hold a historic summit in the Demilitarised Zone next month -- and that the North's leader Kim Jong Un was ready to halt provocative missile and nuclear tests and sit down with its old enemies.
Although Trump's response was positive, his administration followed it up with another sharp rebuke when it declared that it had formally concluded that Kim's regime had last year murdered his half-brother in a Malaysian airport with the banned VX nerve agent.
Trump also sounded a note of warning, signaling the threat of military action remains on the table should talks fail to make headway, and his administration said it would press ahead with potentially provocative joint war games with South Korea.
The United States says Pyongyang is testing -- and will soon complete -- an intercontinental ballistic missile capable of delivering a nuke to the continental United States.
That ominous technological breakthrough would put cities like Los Angeles and even New York in striking distance of a hostile regime, something that is unthinkable to many in the West Wing.
The offer of talks, not yet publicly confirmed by North Korea, is a tantalizing one for the White House -- offering a possible off-ramp from the road to a bloody war. But it is also fraught with risks.
On multiple occasions, Kim's father Kim Jong Il dangled the prospect of talks and denuclearization as a means of buying time, easing sanctions and dividing South Korea from its allies.