In a speech at Stanford University in California last week, Biegun said that he would be aiming in his talks for "a roadmap of negotiations and declarations going forward, and a shared understanding of the desired outcomes of our joint efforts".
"We have some hard work to do with the DPRK [North Korea] between now and then", Mr Biegun added, looking ahead to the Hanoi summit. "It will take place in Hanoi, Vietnam, on February 27 & 28", Trump said on Twitter.
"Special Representative Biegun and Special Representative Kim agreed to meet again in advance of President Trump and Chairman Kim's second summit".
Earlier this week, Trump announced the dates for the second summit with Kim and said it would be held in Vietnam, but the city had not been disclosed. But he didn't say where in Vietnam they would meet or what specifically they would discuss.
"The South Korean government will, as it has been doing, closely communicate and cooperate with both North Korea and the US, and do its best for the success of the US-North Korea summit and the establishment of a lasting and durable peace on the Korean Peninsula", the minister said.
Experts say Kim is determined to win relief from USA -led sanctions to help revive his country's troubled economy, while Trump, faced with domestic problems such as the Russian investigation, needs foreign policy achievements.
If the second summit fails to produce a breakthrough, skepticism about the current nuclear diplomacy will grow.
The North must immediately disclose its nuclear and missile programs.
Following an ICBM test on November 29, 2017, when the Hwasong-15 was sacked, Kim Jong Un declared North Korea had "finally realized the great historic cause of completing the state nuclear force". He may surprise some but he won't surprise me, because I have gotten to know him & fully understand how capable he is.
The "Army-Building Day", which commemorates the 1948 establishment of the Korean People's Army, is one of North Korea's biggest national holidays.
Biegun landed at Osan US Air Base Friday evening, foreign ministry spokesman Noh Kyu-duk told AFP.
"What is unique about the next Moon-Kim summit is that it will likely be held in Seoul, which would make Kim the first North Korean leader to visit the South's capital since the end of the 1950-53 Korean War", KJD reported, quoting a letter Kim sent to Moon a year ago in which he said he was willing to visit Seoul.