HyoRiSoo, an unofficial unit of Girls' Generation consisting of Hyoyeon, Yuri, and Seoyoung, appeared on MBC's entertainment program 'What Do You Do When You Play?' on the afternoon of the 20th to perform the OST 'When Stars Fall'. HyoRiSoo was born through Hyoyeon's YouTube content 'Hyoyeon's Level Up' last year and is positioning itself as a rival to TaeTeaSeo (Taeyeon, Tiffany, Seohyun). On the broadcast, HyoRiSoo spontaneously rushed to the center stage when the song's interlude played and completed a skilled performance by coordinating their choreography without prior preparation. Yoo Jae-suk was fascinated by their signature moves and even attempted to follow the choreography, eliciting enthusiastic reactions from the cast. Haha expressed admiration, saying 'It's not funny, it's cool!' The three members demonstrated impressive teamwork and chemistry despite minimal preparation, showcasing a polished stage performance. HyoRiSoo, which started as a playful project on YouTube, is now generating buzz for expanding their activities into actual OST performances.