North Korean leader Kim Jong-un has departed for Hanoi by train for talks with US President Donald Trump.
He arrived at the Chinese border city of Dandong after 21:00 local time (13:00 GMT) on Saturday.
The much anticipated second US-North Korea summit is scheduled for Wednesday and Thursday in the Vietnamese capital.
It follows a historic first round of talks last year in Singapore. All eyes will be on what if any progress is made towards "denuclearisation".
The departure, confirmed by North Korean state media, is the first official acknowledgement that the talks are taking place.
The state media report said Mr Kim would pay a "goodwill" visit to Vietnam as part of the trip.
He is thought to be travelling with his sister Kim Yo Jong and one of his key negotiators, former General Kim Yong Chol.
Why are they meeting again?
"We fell in love," Mr Trump told a rally last September of Mr Kim. "He wrote me beautiful letters."
Despite the flowery words, the months following the first summit last June were characterised by frosty and sparse contact.
This meeting is expected to build on the groundwork of that meeting and address the thorny issue of denuclearisation, where experts say little progress has been made.
Days before the Hanoi meeting, the agenda remains unclear.
What did the last summit achieve?
The first summit last June in Singapore, between two leaders who had previously only exchanged vitriol, was certainly a historic moment.
However, the agreement they signed was vague on detail and little has been done about its stated goal of "denuclearisation".
Donald Trump promised to scale back the US-South Korea military exercises that angered the North, but in the months that have passed many have queried what he got in return.
Moves like the dismantling of a key rocket site in the North last summer are little more more than a gesture, experts say, given the North made no commitment to halt weapons development or shut down missile bases.
However, lower-level negotiation channels have recently seen activity, which could mean more goes into a Hanoi declaration.-BBC
