The other long awaited cameo (guest) appearance for Crash Landing on You is out on episode 13! When the news first confirmed that Choi Ji Woo will be making the cameo in the drama, I immediately linked to the pact Se Ri made with them before 1st escape.
Kim Ju Muk (Yoo Su Bin) is a K-drama fanatic in North Korea and also the bridge between Se Ri and the rest when she first started there. During the mini award ceremony before her 1st escape, she gave them each a choice of 2 different rewards. (1) Claim immediately (2) Claim when the country unify.
Will be waiting for Lee Seung Gi‘s guest appearance as well! Wonder where will he appear…
Source (1)