As "Game of Thrones" hits the San Diego Comic-Con, the panel with the cast, producers, and George R.R. Martin has revealed several things about the upcoming season.

For one, season 4 will have a very brutal production schedule.

"It's the toughest production schedule we've ever had," says showrunner David Benioff. "We got more action, which is obviously more time consuming. It's a brutal shooting season ahead. But if we can make it through, yeah, I think it's going to surpass season 3."

"The last 3 episodes, there's so many scenes we've been waiting for so long to do. And it just gets more and more fun to write for these characters. After three years of doing it, we have that much more comfort to make everything uncomfortable for them. We're very excited for it. Season five gives me nightmares, but [not season four]."

"I just finished reading the scripts, and the script these guys have turned out are my favorite so far of the whole series," echoes Peter Dinklage.

At the same time, the "Game of Thrones" originator George R.R. Martin very much admits to feeling the pressure of finishing the epic saga, now that the show is moving to season 4.

"The locomotive is coming up behind me and I'm still laying the tracks."

Watch the entire Comic-Con panel below: