Fans are eager for IU to release an unreleased song she performed at her concert.

On September 21, IU surprised the audience by performing an unreleased track during the first night of the encore of her HEREH World Tour concert for "The Winning" at Seoul World Cup Stadium. With one final show set for September 22, this will mark the closure of her successful world tour.

During the concert, IU performed a song titled "Bye Summer," which she explained was a special piece reflecting on the cherished memories she made over the summer and throughout the tour. She told the crowd there were no plans to release the song, but after hearing it, fans expressed their desire for an official release, calling it beautiful.

Watch IU's performance of "Bye Summer" below.

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