Singer IU held a surprise concert with indie band Hyukoh.

On Tuesday, IU appeared at Hyukoh's concert that was held in front of a cafe in Seoul's Hongdae district as a special guest.

Upon her surprise appearance, the acoustic pop star played an acoustic rendition of Lee Moon Se's "Old Love" and also joined Hyukoh for a duet of "Gondry."

This was a surprise appearance that even her fans did not know about. The area for the concert was not big so it seems that she didn't announce it in case too many fans gather in the small area.

After the concert, many internet users posted pictures of IU and Hyukoh during the concert on online community forums and SNS accounts.