The cast has wrapped up shooting on the last episodes of the desert island drama, and the final installment will air in the U.S. later this month (23May10).
And Kim, who has played Jin-Soo Kwon on the show for the last six years, is "sad" to wave goodbye to the series after developing such close bonds on set.
He tells Parade, "I have to be honest, I'm still in the process (of letting go of Jin-Soo Kwon). I really have grown very fond of him. It's always weird to me when actors talk about their characters in the third person, but in this case, I've lived with this character for six years so he's become a part of me. So it's going to be like a favourite suit that I won't be wearing again and that's a little bit sad.
"(Shooting the final scenes were) a little bit like the last week of high school where you're about to graduate. You know if you're going to college or not and you know that your grades don't really matter anymore and you're just out there to have a good time with your friends. But you still had to go to class! I think, at the very end, it was really tinged with a lot of sadness and reflection about the last six years that we've all spent with each other."