However, many fans rebutted this and shared old photos of her, claiming that her features have always stayed the same.
They said that IU did not look as good when she first made her debut as she was chubbier and did not put on makeup properly.
Some people also claimed that IU went for skin-whitening surgery, but this would only have temporary results and did not lighten one's skin permanently.
According to Koreaboo, she supposedly looked darker in the past due to her old gloomy concept, use of dark ballads and the company wanting her to look more mature.
However, her pre-debut pictures show that IU has always had radiant and fair skin. Even her eyes look the same in the last 14 years.
A picture that shows IU posing beside a doctor at a clinic has also been mistaken as her going for plastic surgery.
"However, if you look at the original picture below the place is called ‘ID Esthetics and is a dermatology clinic," said the Koreaboo report.
Her agency later explained that IU was at the clinic for skincare purposes and that it would be impossible for her to get surgery, due to her packed schedule.
They added that IU had left a photo and her signature behind because she had nothing to hide.
See all the pictures of IU over the years in the gallery.