First teased a while back, it was revealed Sunday on Talking Dead which character will be crossing over between AMC’s The Walking Dead and its spinoff companion series Fear the Walking Dead. While some thought maybe this “crossover” would simply be one character popping over to the other show for one episode, this is actually a full changing of the guard. Lennie James, who plays Morgan on The Walking Dead, will depart the flagship series by the end of the show’s current eighth season to join the cast of Fear the Walking Dead. He’ll make his debut in Season 4 of the spinoff series, airing in 2018.

James made his The Walking Dead debut all the way back in the pilot, playing one of the first characters that protagonist Rick Grimes (Andrew Lincoln) encounters after waking up in the abandoned/zombie-infested hospital. He returned for one episode in the show’s third season for a surprise appearance, popping up again for two more episodes in Season 4 before becoming a series regular in Season 5.

It’s unclear how Morgan’s exit will be handled. He could conceivably be killed off since Fear the Walking Dead takes place in a different, earlier timeline than The Walking Dead, so the idea presumably is to fill in the gaps of Morgan’s story.

After debuting to pretty high numbers, Fear the Walking Dead’s ratings entered a downslope in Season 2 before resting around 2.3 million viewers towards the end of its third season. AMC no doubt hopes this crossover brings in more eyeballs to the spinoff series, but the flagship show isn’t doing so hot either. Once untouchable, The Walking Dead’s numbers started to decline in Season 7 and have somewhat plummeted in the current eighth season. The show is far from the danger zone, but in a sign that no series is immortal (unless your name is NCIS), it's now a far cry from its heydey as the highest-rated show on TV by a country mile.

The Walking Dead showrunner Scott M. Gimple promises there’s still “a lot of story” left for Morgan on the main series, adding “Morgan’s arc on The Walking Dead Season 8 positioned him for the story on Fear. It was also important to see Fear’s world and characters through new yet familiar eyes.”

The Walking Dead Season 8 is currently airing on AMC.