On March 18, 2026, Kim Sejeong shared a heartfelt Instagram update, captioned "A happy tenth letter," announcing that her fan-concert had successfully come to an end.
In the photos, Kim Sejeong smiles in a cute white hat, strikes a confident pose in a red checkered outfit, and beams elegantly in a white dress. She added a warm message: "Wrapped safely! Thanks to you, I was overflowing with happiness. I love you, world."
Fans reacted enthusiastically: "You worked so hard, Sejeong! Congratulations on the successful 'Tenth Letter' fan-concert," and "Daisuki, please perform in Japan again."