Lee Youngseo, a former member of ILLIT, has been seen getting ready for her debut in High Up Entertainment's upcoming girl group. Recent sightings of Lee Youngseo filming alongside the group's debut lineup at High Up Entertainment have excited K-netizens. The new girl group, set to be launched in the latter part of 2025 by the agency known for managing STAYC, is highly anticipated.

Lee Youngseo gained recognition from K-Pop enthusiasts for her participation in the JTBC idol survival show 'R U Next?' in 2023, where she secured the 2nd position and a place in ILLIT. However, prior to ILLIT's debut, Lee Youngseo parted ways with the team, as confirmed by BeLift Lab.

Contrary to previous speculations suggesting Lee Youngseo left the music industry to focus on her education, it has now been verified that she is working with High Up Entertainment. The new girl group's lineup also includes Na Haeun, a former trainee of SM Entertainment, and Park Yeeun, a contestant from 'I-Land 2'. Additionally, ILLIT has released a teaser highlighting their upcoming mini-album 'bomb'.