Reza Fahim and starring The Weeknd and Lily-Rose Depp, “The Idol” is “set against the backdrop of the music industry” and “centers on a self-help guru and leader of a modern-day cult, who develops a complicated relationship with an up-and-coming pop idol.”In addition to the series order for “The Idol,” HBO revealed these additional cast members for the drama: Suzanna Son (series regular), Melanie Liburd (recurring), Tunde Adebimpe (recurring), Steve Zissis (series regular), Troye Sivan (series