While we don't yet know what will happen in The Walking Dead finale this coming Sunday, we do know it has had a profound effect on the AMC series' cast. This is not an episode that will leave fans smiling. Andrew Lincoln was left so traumatized by the script for this Season 6 ender, it was the only time he ever showed up late for work. Lauren Cohan was so sick at her stomach and distraught, she didn't want to go to work at all. And poor Josh McDermitt had to throw his script across the room just to get away from it. Now, the episode has been viewed by Daryl Dixon himself, and Norman Reedus reveals that it literally left him speechless.

Yes, Last Day On Earth is going to crush souls and make grown men cry. At least that's what we guess after listening to the participants tell the story. The cast has been very vocal about how upsetting this episode was to both read and film. Now, we know that it's equally heartbreaking to watch. The Walking Dead Season 6 finale premieres this Sunday, April 3, at 9pm on AMC and it promises to be one of the most talked about TV moments in history. Says Norman Reedus about Last Day On Earth.

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"I saw a little rough cut of it. And it's the most hardcore episode we've ever shot. I couldn't speak after I watched it. And, of course, I knew what was happening, and what was going to happen, and who was involved, but I got to tell you, I couldn't speak for like an hour. And then I just was bombarded with phone calls on my drive home. But that was a rough, rough, rough cut. I will say that it might be the best episode we've ever shot of the show."

Last Day On Earth will introduce the original comic book character Negan, a fan-favorite who likes to bash in people's heads with his baseball bat lovingly referred to as Lucille. He is a super-villain who is very hardcore. And in the comics, he chooses one of the Alexandria residents at random to kill. The original victim, as you might know, is Glenn. But many fans suspect that this moment will be changed for the TV show. In fact, most fans speculate that the only victim of Negan's bat can possibly be Daryl.

Norman Reedus won't divulge whether or not he'll get to meet Lucille face-to-face. But he has nothing but praise for Jeffrey Dean Morgan, who is playing Negan. The actor says this about his co-star.

"I've known Jeffrey for a long, long time. He's a friend of mine, and I really respect him as an actor. And as a dude, he's just the best. It's weird to have such a nice guy playing such an a-hole, you know what I mean? But that's just the testament to how good he is. So I'm excited to see where he goes and what happens to that guy."

Executive producer and VFX maestro Greg Nicotero directed Last Day On Earth, his second straight season finale. He has become the go-to guy for big episodes. And it sounds like he really knocked it out of the park this time around. About what could possibly be his last episode ever, Norman Reedus had this to say in regards to how Nicotero handled the episode.

"Talk about the inner circle, Greg's one of those people who's with you from the get-go, from the very start of everything you do to the very end of everything you do. He's one of my best friends and I've watched that guy just blow the hell up. He's an unstoppable force right now on the show."

While Jeffrey Dean Morgan is only being introduced in the final third half of Last Day On Earth, he will be a series regular in The Walking Dead Season 7. Will his presence loom big enough to cover Daryl's shadow if that is indeed whom he kills off? We'll all have to wait and see. We'll get to watch Last Day On Earth for ourselves this Sunday. But it sounds like it will be too much for some of us to handle.