Real Girls Project •
Lee Su-ji () as Suji/Suah •
Heo Youngjoo () as Youngjoo •
Sori () as Sori •
Yukika Teramoto (寺本來可 / ) as Yukika • Kwon Ha-seo () as Haseo • Lee Jee-won () as Jeewon • Jung Tae-ri () as Taeri •
Mint () as Mint • Lee Ye-eun () as Yeeun • Cha Ji-seul () as Jiseul • Chun Jane () as Jane
Red Queen •
Jo So-jin as Yeri •
Lee Ka-eun as Kang Shin-hyuk, the former Producer of Red Queen. •
Park Chul-min as Shim Min-chul, CEO of 825 Entertainment. •
Kang Ye-seul as Yeseul, the girls' manager at 825 Entertainment.
Other characters • Heo Joungjoo as Joungjoo, Youngjoo's younger sister who is a singer-songwriter. •
Lee Coco as Coco, an internet broadcast MC. •
Jin Nayoung as Nayoung, Sori's friend. •
Bae Seul-ki as Kim Dan-oh, a composer and vocal trainer.
Cameo •
Kim Jung-ah as vocal training judge •
Jung Tae-woo •
Euna Kim as a rapper •
Gowoon as Bomi •
Jung Hee-chul as Haseo's brother • Lee Moo-saeng as Chief Yang ==Production==