| Name | Character | Episodes |
|---|---|---|
| IU | Go Hajin / Lady Hae Soo | 20 |
| Sung Dong-il | General Park Soogyeong | 20 |
| Park Ji-young | Queen Yoo / Queen Shinmyeong | 20 |
| Lee Joon-gi | Wang So (4th Prince) | 20 |
| Baekhyun | Wang Eun (10th Prince) | 20 |
| Jung Kyung-soon | Queen Hwangbo / Queen Shinjeong | 20 |
| Kang Ha-neul | Wang Wook (8th Prince) | 20 |
| Byeon Woo-seok | Hajin's boyfriend | 1 |