Kim Hyok-chol, North Korea's special representative for U.S. affairs, arrived in Beijing on Tuesday before heading to Vietnam. 

Kim’s counterpart is U.S. Special Representative for North Korea Stephen Biegun. The two envoys are expected to draft the agreement for the second U.S.-North Korea summit set for next Wednesday and Thursday in Hanoi. 

This would be Kim and Biegun’s second pre-summit talks after their initial negotiations in Pyongyang earlier this month.

While Kim and Biegun discuss the agenda, Kim Chang-son, North Korean leader Kim Jong-un's de facto chief of staff, is expected to discuss protocol matters with Daniel Walsh, deputy chief of operations at the White House. Both Kim Chang-son and Walsh arrived in Hanoi last week.