Harley Quinn might be wreaking havoc in Gotham City sooner than we thought. After much speculation about when she would appear, one Gotham star has finally given us a definitive answer.

"She's going to be in the finale. Stay tuned," David Mazouz, who plays Bruce Wayne, told Movie Pilot during the Heroes & Villains Fan Fest in London. We broke the news back in January when executive producer John Stevens told TVGuide.com, "Well, it turns out that the villainess will likely be introduced even before the end of this season. We might see [her] in Episode 22."

In DC folklore, Quinn starts out as Dr. Harleen Quinzel, an up-and-coming psychiatrist for Arkham Asylum tasked with helping the Joker. Unfortunately, he manipulates her to the point where she is obsessed and devotes her entire life to making him happy and causing mayhem. She eventually breaks him out of the institution for the criminally insane and the rest is history.

With Joker already making his presence known on the series, it's only a matter of time before she makes her triumphant debut. Erin Richards, who plays Barbara Kean, has hinted at a major change for her character making her the prime candidate for Quinn.

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"Harley Quinn seems to like destruction for destruction's sake, and that's wonderful, but I feel like Barbara has more of a plan. She's a little bit more intellectual in her approach toward climbing the ladder and taking over the underworld," she told Cinema Blend.

"And I think if she was to then morph into Harley Quinn, there would have to be something that happened that sort of stripped away that kind of scheming side of her so that she would just become, I guess, unhinged in the world...That madness and mayhem that comes along with The Joker, because obviously they're a team."

Reps for Fox have not yet responded to our request for comment.

Gotham airs Monday nights at 8/7c on Fox.