'Gotham' season 3 cast news, spoilers: 'The Walking Dead' alum cast as Mad Hatter; new poster teases Court of Owls

"Gotham" has cast its Mad Hatter.

Following a spate of casting announcements for its upcoming season 3, Fox has confirmed that "The Walking Dead" grad Benedict Samuel is joining the cast of "Gotham" in season 3 as the Mad Hatter, also known as Jervis Tetch.

According to the official casting description from Fox, the Mad Hatter is a talented hypnotist on the verge of insanity. He arrives in Gotham determined to find his sister, Alice, a young lady who disappeared in the city years ago.

"It is anyone's guess just how far down the rabbit hole he's willing to go in order to find her," the description for the new character reads.

Samuel had a recurring role in "The Walking Dead" season 6 as the Wolf who was caught by Morgan (Lennie James). Carol (Melissa McBride) later found Morgan trying to rehabilitate the prisoner in Alexandria, but Morgan eventually ended up having to kill the Wolf.

Prior to "The Walking Dead," Samuel appeared in "The Walk" (2015), which was directed by Robert Zemeckis, and in the Australian miniseries "The Beautiful Lie."

The actor joins fellow "Gotham" newcomers James Carpinello (Mario Falcone), Maggie Geha (Poison Ivy), and Jamie Chung (Valerie Vale).

Several other new villains, specifically the Tweedle Brothers and Solomon Grundy, have yet to be cast.

Meanwhile, Fox has just released a new poster for "Gotham" season 3 which announces the coming of even more villains. The new season 3 poster features an owl mask as well as the words "All Will Be Judged," pointing to the villainous Court of Owls.

While the Court of Owls have been part of the show for a while, the new poster indicates that they will be a major presence in season 3.

In the comics, the Court of Owls was a secret society/organized crime group made up of mask-wearing men and women. They controlled Gotham and kidnapped children, who they then turned into assassins.

"Gotham" season 3 will premiere Monday, Sept. 19, at 8 p.m. ET on Fox.