The homepage of the 'Special Exhibition of Goryeo Palace Kaesong Manwoldae by the South-North Joint Investigation Team' (literal translation) has been recently released.
This page is to advertise the special exhibition of the artifacts discovered by the South-North Joint Investigation along with the 1100th anniversary of the establishment of Goryeo Kingdom and the '2018 PyeongChang Olympic & Paralympic Winter Games'.

The facial expression of Kang Daniel with firm and calm pose perfectly suits the outfit.
This picture suggests that Kang Daniel in traditional Korean attire is to advertise the exhibition's program for the experience of wearing the outfit from the Goryeo era.

The group Wanna One is working as an honorary ambassador of this special exhibition.

The exhibition is for free, and it will be open from February 10 to March 18 at the constructed exhibition center inside Daegwallyeong High School near PyeongChang Olympic Stadium.
Yet it will be closed from February 26 to March 8, the time between the next day of the closing ceremony of the 2018 PyeongChang Olympics and the day right before the opening ceremony of Paralympic Winter Games.
The '2018 PyeongChang Olympic & Paralympic Winter Games' begins from February 9.
(Credit= 'Special Exhibition of Goryeo Palace Kaesong Manwoldae' Official Website)
(SBS Star)