In the last episode of "The Unit," the show's judges HyunA and rapper San E came across a familiar face in front of them. Singer JOO appeared to deliver a performance in the hopes of getting another chance to perform on stage.

As fans of the singer would know, JOO, San E, and HyunA were all once artists under JYP Entertainment. JOO and HyunA were training to be a part of Wonder Girls, and from the two of them, only HyunA made it to the group but she eventually left the group and signed onto Cube Entertainment to perform as a member of 4Minute.

When JOO was asked why she decided to join an idol rebooting show, the singer revealed that she originally dreamt of becoming an idol, and even trained for it as well. However, she ended up debuting in the industry as a ballad singer. JOO went on to explain that she thought about whether or not she should try out for "The Unit" knowing that the public knows her as a ballad singer. She thought the public might feel disconnected if she joined, but on the other hand, she also wondered if she would ever get an opportunity like this again.

HyunA then explained to her fellow judges and the audience the history they have together, breaking into tears before JOO went to perform "The Face I Want to See" by Min Hae Kyung.

After her performance, San E also expressed his thanks to JOO, and said that from watching her muster up the courage to stand on that stage, he became motivated, and that he could feel how sincere she was. HyunA went in to point out that JOO seemed happy when the music really started and thought that this was a good performance for her.

JOO ultimately moved forward with all six boots, also known as "Super Boot" from the judges and the audience. JOO happens to be one of the many who had received all six boots for their performance. The members of groups IM and Melody Day have also been given the Super Boot for their respective performances by the audience.

The four-membered girl group Melody Day performed "Twinkle" by SNSD-TaeTiSeo while the boy group IM performed "Very Nice" by Seventeen.

Melody Day debuted in 2014. They revealed that the reason they joined "The Unit" was because they lost the public's attention due to the long breaks they had in between comebacks. Their performance earned them the Super Boot, with one of the judges, Jo Hyun Ah of Urban Zakapa, praising them and telling them that they were born with the abilities to hit the high notes in the song.

IM debuted only this year, and have already impressed the judges with their performance. Ki Joong, one of the group's members, was already known to be the youngest male contestant on the show. Ki Joong also served as the male center in the show's music video "My Turn." Rain, praised Ki Joong's charismatic gaze to which he asked him why he was staring at him as he performed. Ki Joong then replied that it was because Rain was very good looking, making everyone laugh.

"The Unit" airs Saturdays 9:15 p.m. KST/9:15 a.m. EDT on KBS2.