We have good news and bad news for fans of AMC's The Walking Dead today. The good news is that the network has renewed the popular zombie series for Season 4. The bad news is that showrunner Glen Mazzara will leave the series after finishing work on Season 3. Here is a joint statement released by AMC and Glen Mazzara.

"Today, AMC announces the Season 4 pick-up of The Walking Dead.

AMC also jointly announces with Glen Mazzara today that for future seasons, the two parties have mutually decided to part ways. Glen guided the series creatively for Season 2 and Season 3. AMC is grateful for his hard work. We are both proud of our shared success.

Both parties acknowledge that there is a difference of opinion about where the show should go moving forward, and conclude that it is best to part ways. This decision is amicable and Glen will remain on for post-production on Season 3B as showrunner and executive producer."

Glen Mazzara also issued another statement.

"My time as showrunner on The Walking Dead has been an amazing experience, but after I finish Season 3, it's time to move on. I have told the stories I wanted to tell and connected with our fans on a level that I never imagined. It doesn't get much better than that. Thank you to everyone who has been a part of this journey."

The network hasn't announced who will step in for Glen Mazzara as the showrunner in Season 4. Stay tuned.