After the huge success of "Suicide Squad," Harley Quinn will star in "Gotham City Sirens" along with Poison Ivy and Catwoman. Fans are speculating on the details of the casting and the plot, but Warner Brothers has been mum on other details of the movie, even its release date.

Margot Robbie is set to reprise her role as the Clown Princess of Crime. ComicBook.com is fanning rumors have it that Megan Fox is interested in playing the dangerous botanist, teasing that the actress has been reading up on Harley Quinn from her place at the studios. Meanwhile, Anne Hathaway has previously expressed her wish to don her cat suit again. Nothing is confirmed, however, but fans are abuzz with excitement at the possibilities.

Movie Pilot teases that the movie will follow its comic book counterpart in terms of story arc. In the comics, Harley and Ivy are partners in crime and in bed. They get into all sorts of mischief together. Later, they take Catwoman in to make a trio of villainesses, with the intention of finding out Batman's true identity which Selena already knew. This scenario sets the stage for much character growth for the three women.

Harley's romance with Ivy served as her release from Joker -- a relationship established in Suicide Squad as dangerously demented and abusive. In a tumult of memories, Harley in the comics decided to kill the Joker, but freed him instead. Ivy battled them trying to save Harley from her attachment to her former lover, but Harley defeats her. Before Harley and Joker escape, Batman and Catwoman catch all three and lock them up at Arkham. In all this, Ivy realized that Harley was addicted to Joker and vowed to help her get over him. The story complicatedly progressed to the three villainesses separating ways.