The mysterious man in "Fxxk U" teaser video is unveiled, and it's none other than actor Joo Ji Hoon.

On January 27th, Apop Entertainment released some new still cuts of the actor from the MV. He showed off his cool and charisma look which has attracted much attention. It is said that him and Gain are close to each other so he decided to star in the MV to support her comeback.

In addition, Gain will release full song of "Fxxk U" at midnight on January 27th while her new mini album will be released on February 6th.