A special collaboration stage at this year’s SMTown concert has quickly gone viral among fans. On January 31, during Day 1 of “SMTown Live” in Fukuoka, Japan, aespa’s Karina and Winter joined Red Velvet’s Irene and Seulgi for a performance of f(x)’s well-known track “Chu.”

The unexpected lineup drew immediate attention, as the four idols represent different generations of SM Entertainment’s girl groups. Their joint appearance created a strong sense of continuity within the company’s artist lineup, while also delivering a fresh take on a familiar song. Originally released by f(x), “Chu” remains a nostalgic favorite for many K-pop listeners, making its revival on a modern stage particularly meaningful.
Short clips from the performance spread rapidly across social media, with fans expressing excitement over both the rare collaboration and the emotional resonance of the song choice. Many noted how the performers’ distinct styles and stage presence complemented one another, resulting in a balanced and engaging performance.
Overall, the stage served as more than a one-time collaboration. It functioned as a tribute to SM Entertainment’s musical legacy, blending past and present through a reinterpretation of a classic track. By bringing together artists from different eras, the performance highlighted both the enduring appeal of “Chu” and the evolving identity of SM’s female artists.