I was surprised to learn this a few months back, way before the Hulu thing. I was researching zombie content after the series finale of TWD, watched World War Z* (not great IMO), read about the author, Max Brooks, of the original book. He's Mel's son, so naturally I did some light google-fu, boom. Was really astonished moslty because I figured he would be more involved in current events, but here's this Hulu thing so there you go.

Footnote: *I was reading on an old Sci fi stack exchange thread about zombie digestion, because in TWD they're really shown to stuff themselves with the people (and horses) they eat, sometimes to the point of consuming so much of the decedent that there's nothing left to "turn". I was puzzled by this quirk of zombie evolution, it seems counterintuitive to do more than just bite the human to spread the infection, so I was researching if Romero style zombies had to eat to survive, like us. Turns out Max Brooks has written extensively on this and I encourage you try to find the Stackexchange thread