Image copyright Getty Images Image caption Kim Chang-son was also seen last year scouting out hotels in Singapore

The "butler" of North Korean leader Kim Jong-un is in Vietnam ahead of a summit meeting with US President Donald Trump set for next week.

During his visit to the capital city of Hanoi, the de-facto chief of staff Kim Chang-son, has been seen checking out potential summit venues.

Kim Jong-un will meet Mr Trump on 27-28 February for a planned second meeting.

Their first meeting, in Singapore last June, was the first time the two countries' serving leaders had met.

Who is Kim Chang-son?

A close aide of Kim Jong-un, Kim Chang-son, who has previously been referred to by South Korean media as the "butler" to the North Korean leader, arrived in Vietnam over the weekend.

Kim Chang-son is currently the country's de-facto chief of staff, but has been in the Kim family's employ for many years.

According to NK Leadership Watch, he was previously the director and chief secretary of the National Defence Commission. He was also Kim Jong-un's chief aide, and was responsible for his schedule and itineraries.

What is he doing in Vietnam?

Mr Kim has been seen checking out possible venues for the summit in Hanoi, according to Reuters.

He was seen visiting a government guesthouse and the Metropole and Melia hotels, located in the centre of the city.

Image copyright Reuters Image caption Mr Kim at the Metropole hotel in Hanoi

He is also likely to be discussing protocol and security matters with his US counterparts.

Daniel Walsh, the deputy chief of staff for operations and assistant to the US president, and Alex Wong, the US deputy assistant secretary of state for North Korea are both already in the capital.

What can we learn from him being there?

It's a clear sign that the summit is moving ahead as planned.

During the June summit in Singapore last year, Mr Kim had also been seen scouting out different hotels ahead of the summit.

So it's no surprise that he has been sent out again to do the same in Hanoi. If all goes to plan, it will be a matter of time before the venue is announced.

What do we know about the summit?

Not much.

It's not clear what exactly will be on the agenda, though some experts suggests that there could be discussion around the dismantling of North Korea's Yongbyon nuclear facility.

The first summit saw the two leaders agree to work towards denuclearisation, but there were no details on what this would entail.

Image copyright AFP Image caption The first Kim-Trump summit was historic but nothing concrete was really achieved

It's unlikely that the pair will be able to get away with a vaguely-worded agreement a second time, observers say, and many will be watching to see if anything concrete comes out of the meeting.

Why is it happening in Vietnam?

It is an ideal location for many reasons.

It has diplomatic relations with both the US and North Korea, despite once having been enemies with the US, and could be used by the US as an example of two countries working together and setting aside their past grievances.

Ideologically, both Vietnam and North Korea are communist countries, though Vietnam has rapidly developed since and become one of the fastest growing economies in Asia.

Logistically, Vietnam is well within flight range of North Korea making it easy enough for Mr Kim's personal jet to get to.

Vietnam has also previously hosted high-level summits. The coastal city of Da Nang hosted the Apec summit in 2017 which saw world leaders in attendance. But this time, it will be Hanoi's turn to step up to the plate.