For Robbie, that meant trying to discover who Kayla would be if she was a real person, and the first step in bringing the character to life was to look into the minds of the women she would likely surround herself with. "“I didn’t understand her to begin with,” Robbie told Variety. “But my process is to do a ton of research, consider every single option, know every single situation, scenario, thought and motivation inside and out, so I can step onto set and then let it all go.”