Kim Wooseok and Lee Eun-sang, former members of the boy group X1 from Produce X 101, officially declared that they would collaborate to launch a track for their fans.

Kim Wooseok and Lee Eun-sang shocked their fans in the afternoon of October 7 through posting pictures of them together on their official social media page. This contributed to attracting interest from fans across the world. (via Kpopstarz)

Both K-pop idols are leaning against the rail of a rooftop in one picture and showing off a radiant smile. In another, with Lee Eun-sang putting his arm around Lee Wooseok, the two revealed their strong relationship with their backs shown in the image as they watched the sky.

Moreover, the two are seated on the rooftop in another photograph, enjoying their seat view. The only description included throughout the post was "201914." The teaser amusingly excited their fans, stirring high expectations for the pair.

Both managing labels, TOP Media and Brand New Music, reported on Thursday, October 8, that the pair would be working closely on a joint single, slated for release on October 14 at 6 PM KST.

This will be the first time the two have interacted together as former members from the now-disbanded boy band X1.(via Soompi)

From his first solo record, 1ST DESIRE [GREED], Kim Wooseok debuted in the K-pop scene as a solo artist back in May.

Kim Wooseok has been involved in different domains ever since, such as music, television, and advertisement, including the much-talked-about online drama "TWENTY TWENTY," where he portrays the lead character Hyun Jin.

Meanwhile, Lee Eun-sang managed to debut in the music industry as a soloist in August with his first single release, "Beautiful Scar," where he shares the charms he has kept hidden.

Since then, he has shown his different charms across a range of material and will have his first online fan meeting on October 24, "Beautiful Sky," to bond and perform for his followers.

Since meetings are expected by many people, both in South Korea and abroad, people can stay informed by following their social media profiles. Kim Wooseok and Lee Eunsang's duet collaborative project album will be launched on all big streaming music websites on October 14 at 6 PM KST.