Fox's Gotham has hinted at Harley Quinn's arrival for a long, long time. Now, a new picture reveals a look for Ecco that sees her transformation almost complete.

Actor Francesca Root-Dodson, who plays Ecco on Gotham, posted a picture of herself in Harley Quinn makeup on Instagram. The post also makes it clear that the woman with whom Jeremiah Valeska was dancing in images earlier this week is indeed Ecco, just with a dramatically different look.

RELATED: Gotham's Checkered History of Teasing Harley Quinn

Harley Quinn first appeared in Batman: The Animated Series before making her way to the comics. The immensely popular character is currently played by Margot Robbie in the DC Extended Universe. There was a time when viewers believed Barbara Kean would turn into the series’ version of Harley, especially after she was used as a stage-assistant of sorts to Jerome’s proto-Joker. Ecco has been transforming into Quinn for quite some time, having previously dressed in a costume reminiscent of Quinn.

Jeremiah is now Gotham's version of the Joker, though he won't actually be referred to as such. Showrunner John Stephens previously said that Harley Quinn wouldn't appear on Gotham.

RELATED: Gotham Star Shares Photos of Jeremiah and His Harley

Gotham stars Ben McKenzie as James Gordon, Donal Logue as Harvey Bullock, David Mazouz as Bruce Wayne, Robin Lord Taylor as Penguin, Camren Bicondova as Selina Kyle, Erin Richards as Barbara Kean, and Sean Pertwee as Alfred Pennyworth. It is reportedly scheduled to return on Fox for its fifth and final season on Jan. 3, 2019.