AMC has announced that filming has begun on season 9 of hit zombie drama The Walking Dead. The "All Out War" story arc came to a close in the tense season 8 finale, but even with the threat of Negan neutralized, Rick Grimes could have to deal with internal conflicts next - not to mention the looming dangers on the horizon. He's come a long way from his hospital bed.

The Walking Dead is based on the comic book series created by Robert Kirkman and Tony Moore, which is still going strong after 15 years. The TV show premiered in 2010 and, thanks to widespread critical acclaim, soon rose to become one of the biggest shows on TV. A spinoff, Fear the Walking Dead, debuted in 2015 and is currently airing its fourth season.

The start of The Walking Dead season 9 production was announced via the show's official Twitter account. Although the background is out of focus, a water tower is clearly visible, which is likely one of the projects that Maggie was given the plans for in the "Key to a Future" book that was gifted to Hilltop in season 8. This indicates that the next season will kick off with a bit of a time jump.

Season 9, Day 1. #TWD #TWDFamily pic.twitter.com/c42lyqjrPv— The Walking Dead AMC (@WalkingDead_AMC) April 30, 2018

Recent seasons have seen a gradual decline in viewership, with season 8 seeing the lowest ratings since season 1, but The Walking Dead could rally in season 9. Long-time series writer Angela Kang is taking over as showrunner from Scott M. Gimple (who has been promoted to a new position overseeing all Walking Dead content for AMC), and the Rick vs. Negan storyline that many felt was dragging has come to a conclusion.

As for what's on the way in season 9 - well, it's very possible that the season 8 finale included our first look at the Whisperers, a faction of antagonists from the comics who disguise themselves as walkers and move with herds. The finale also suggested that civil war could be brewing, as Maggie isn't happy about Rick keeping Negan alive.

While you wait for The Walking Dead's return, you can still tune in to Fear the Walking Dead to see crossover character Morgan, who made the journey from the original show to the spinoff in the Fear the Walking Dead season 4 premiere. Who knows - perhaps Morgan making the jump from one show to another is merely the first step in a bigger plan to connect AMC's Walking Dead series.

More: Lauren Cohan is Coming Back For The Walking Dead Season 9

The Walking Dead season 9 is expected to premiere in fall 2018.