BabyMonster's Ahyeon Leaves Group Ahead Of Debut

New K-pop group BabyMonster will debut with one less member than expected -- YG Entertainment just announced Ahyeon has left the ensemble to focus on her well-being.

The label addressed the news in a press release Wednesday ... saying, "Although we are saddened to be unable to introduce Ahyeon as a member of BabyMonster, we made this decision for the sake of the artist's health."

"We will spare no support so that Ahyeon can recover fully and return in good health."

There was speculation 16-year-old Ahyeon was leaving the group for months ... but YG remained tight-lipped on her status up until now.

BM -- which now consists of Asa, Chiquita, Haram, Rora, Pharita and Ruka -- will be YG's first new girl group since BLACKPINK's debut in August 2016.

There's been a ton of hype surrounding BabyMonster ... the group has raked in millions of views on YouTube despite not releasing any original songs.

The remaining members' ages range from 14-21 ... and hail from Korea, Thailand and Japan.