The new MBC Friday-Saturday drama "21st Century Grand Lady," set to premiere in April 2026, takes place in the constitutional monarchy of 21st-century South Korea. This drama depicts a romance that breaks social status boundaries between a woman who has everything as a chaebol but suffers from being a commoner and a man who is the king's son but has nothing. In the drama, IU plays the role of Seong Hee-joo, CEO of Castle Beauty.

Seong Hee-joo was born as the illegitimate child of the Castle Group. She possesses dazzling looks, exceptional intelligence, and a strong competitive spirit, along with business acumen that earned her the Best Entrepreneur Award. However, her status as a commoner is her weakness. Since the aristocracy still holds strong authority in the constitutional monarchy of South Korea, Seong Hee-joo sets a goal to enter into a contract marriage with Prince Ian of the royal family to overcome this limitation. Prince Ian is portrayed by Byun Woo-seok.

Seong Hee-joo is depicted as a born competitor who spares no means or methods to achieve her goals. She harbors ambitions to dominate not only the business world but also the royal family. The drama's development raises curiosity about the strategies Seong Hee-joo will use to accomplish her objectives.

In the released photos, Seong Hee-joo is seen leading a meeting passionately with executives in a professional manner. Her gaze exudes the charisma befitting a company owner. At events, she leaves a strong impression with striking fashion under the spotlight of reporters. As the CEO of Castle Beauty, Seong Hee-joo is a figure who becomes the center of all attention.

IU is an all-rounder loved by the public for music and acting, and through the character of Seong Hee-joo in this drama, she is expected to showcase a unique charm. Seong Hee-joo is portrayed as a character who breaks taboos and carves out her own destiny. The drama centers on her bold moves to seize what she desires.

"21st Century Grand Lady" is set to premiere in April, and anticipation is growing for IU's acting and the character's appeal. This drama is expected to offer viewers a fresh perspective through its unique setting of South Korea's constitutional monarchy. Seong Hee-joo's social status rise project will serve as a core element of the drama.