The popular series, which follows Bruce Wayne as a child, years before he becomes The Batman, shows fans how some of Batman's iconic heroes and villains like Jim Gordon, The Riddler, and Penguin got their starts in Gotham City.
It won't be awhile until we get full-fledged versions of these villains - after all, Bruce isn't even a teenager yet. So, fans were caught off guard last season when it was revealed the future Joker had been hanging around on the show under the guise of Jerome, a red-haired youngster who looks far from the cackling Clown Prince of Crime fans love.
For reference, here's Jerome from season one of "Gotham":
Fox
Though he's gone by a few aliases like Joe Kerr (get it?) over the years, no one has ever given the character an actual name.
And here's one of many iterations of the Joker:
DC Comics
Get ready to see a lot more of him in season 2.
During a conference call with Robin Lord Taylor, who plays the Penguin on the show, he told reporters the Joker's transformation will be one fans will be excited to see this season.
"Definitely what you're going to see with Jerome, who's played by Cameron Monaghan, the Joker," Lord Taylor said. "I think everyone is going to be thrilled, including myself to see how that progresses."
Monaghan shared a few images of himself from the show on Instagram over the past few weeks.
He definitely has that grin down.
Showrunner Bruno Heller previously told ComicBook.com season two will start to dive into The Joker origin story.
"The beginning of Season Two is a big Joker-oriented, or 'how the Joker came to be' kind of story," said Heller. "The beginning of Season Two is the very earliest origins of how The Joker came to be."
Season two of "Gotham" is being touted by the network as the "Rise of the Villains" meaning fans can expect to see more on Selina Kyle, the future Catwoman, Edward Nygma, who will become the Riddler, and the further descent of The Penguin (Lord Taylor) into crime lord Oswald Cobblepot.
Jessica Miglio/FOX
Corey Michael Smith as Edward Nygma on the first season of "Gotham."
Lord Taylor added that the transformation he's most excited to watch in season two will be Edward Nygma's turn into The Riddler, something that will be immediately recognizable on the season 2 premiere.
"My main man, Corey Michael Smith, as Edward Nygma," said Lord Taylor. "His transformation, I just love what they did with the character in the first season in that it was a very slow burn. You got to see the seeds of madness that are being planted there, and that really comes to the forefront in season two. I find Corey to be a very inspiring person to work with. I'm just thrilled to see him embrace the character and watch the character flourish."
Season two of "Gotham" premieres Monday, September 21 at 8 p.m. on Fox.