- Acting for Two: Baek Sung-hyun plays both Ui-gyeong and Ui-gyeong's son Jasan/King Seongjong.
- Completely Different Title: The series has two official English titles: Insu, the Queen Mother and Queen Insunote . The second one is a direct translation of the Korean title. The first one isn't.
- Role Reprise:
- Chae Shi-ra also played Insu in the 1998-2000 series The King and the Queen.
- Chae Sang-woo plays Danjong in this series and in the 2013 film The Face Reader.
- Time-Shifted Actor:
- Ham Eun-jung and Chae Shi-ra play Han Jeong/Queen Insu.
- Choi Won-hong and Baek Sung-hyun play Jasan/King Seongjong.
- Jin Ji-hee and Jeon Hye-bin play Song-yi/Deposed Queen Yun.
- Lee Ji-oh and Jang Hui-ung play Prince Wol-san.
- Lee Wu-ju and Go Yun-hu play Grand Prince Jean.
Trivia / Insu, the Queen Mother