The biggest challenges are in the same vein. It's about retaining all that stuff. Also, the physical stuff is not as easy as we originally thought. I play a lot of sports and I remember saying, "Oh, I'll be fine, running around or doing anything."

I took up boxing to get in shape for filming because it's grueling - all the running, the heat, the yelling, the crying that we do.

I try not to question the choices of the production. They've done such a good job up until now that I'm sure they have the right plan in place. And to be quite honest, we don't even know exactly when it will be coming out.

I'm not much of a horror fan. When it comes to ghost stuff and demon stuff, I can't watch that.

What I learned, in the two months that we shot, I don't think I could have learned in two to four years of drama school. It's invaluable to me, and that's been the most fun. It's been nice to let this be a learning experience in everything.

The book is about zombies, in that it is the over-arching theme, but what's going on is the story of these people and how these survivors deal. I think that's so much more of an interesting story, and that's what really gets and hooks these readers into the book and the show. It's a mix of fans of drama, fans of AMC, fans of horror and fans of Frank [Darabont]. It's a lot of people just coming together and realizing a genre doesn't have to be fixed in one specific detail.

Confidence. That's huge as an actor. Confidence can get you a long way. Maybe it's a cultural thing, being Korean, but my first reflex has always been to exude humility - but it doesn't help you in acting. For acting, humility isn't the best thing. It'll weaken your work. So it's a head game for me. "Can I really be confident in knowing my skill set is down? Can I perform like I own this role?"