SEE ALSO: BTOB announces solo concert 'This Is Us'
On August 9, insiders revealed Ilhoon is the lyricist behind the former Rainbow member's first solo title song "Giggling", and he's also featured in the track.
This is Jisook's official solo debut as well as her first song to be released under new agency Dmost Entertainment. Though she's been active on shows like 'Mask King', fans haven't seen her on stage with her own song since Rainbow's disbandment.
Stay tuned for updates!