After a year of dating, celebrity couple UEE of After School and Lee Sang Yoon have parted ways. Sources, however, reveal that the reason for the break up is uncertain.

An insider says that UEE and Lee Sang Yoon broke up very recently. "As of December 31 of last year, the two had a good relationship," allkpop quotes the source. "I don't know everything going on in their personal lives, but you don't know what's going to happen between men and women. They just suddenly broke up."

The break up is also confirmed by Pledis Entertainment, UEE's agency. The company states that it is believed the former couple broke up due to their busy schedules.

According to Koreaboo, UEE and Lee Sang Yoon publicly admitted their relationship in May 2016, but sources reveal that they began dating as early as January 2016. They were introduced by a mutual friend and immediately fell for each other. Dating rumors first came up when the pair was photographed together at the MAMA 2016.

Before the UEE and Lee Sang Yoon dating rumors were confirmed in May 2016, the "Twenty Again" actor said during his January 2016 fan meeting in Osaka, Japan that he was seeing someone. When a fan asked if he already has a boyfriend, Lee Sang Yoon answered in the affirmative.

Meanwhile, reports reveal that Pledis Entertainment is preparing individual activities for UEE as well as fellow After School member Nana. UEE currently stars in the drama "Illumination" with Jin Goo and Lee Yo Won. The idol-actress plays Se Jin, a character described as "spirited but with a poor background."

"I had a lot of worries about how to portray her.  I'm learning a lot from the director, writer, and my seniors on how to express Se Jin, so I will do my best and show a good image," UEE said about her role.