Gotham City Sirens was proposed film follow-up to Suicide Squad and based on the group of the same name. Set in the same continuity, the film would have focus on Harley Quinn, Catwoman and Poison Ivy. David Ayer was scheduled to direct the film, with the Joker as a potential antagonist. The screenplay was to be written by Margot Robbie and Geneva Robertson-Dworet.
Though production was set to begin in Summer 2017, hierarchy changes at WB after the AT&T purchase led to it being postponed and eventually dropped in favor of Cathy Yan's Birds of Prey. However, some commentators have speculated that production on the film might start again.[1]