No premiere date announced. The new PV is here. Check out the ANN article for additional information. Synopsis of the source manga from AniList:
A romantic comedy unique in the history of Corocoro Comics! The slime created by the boy Kotarou can transform into a super beautiful girl! Kotarou is constantly getting pushed around by Puniru’s freewheeling antics. It’s a joyful and exciting life every day!
Looks cute but I’m pretty confident I am not the target audience.
Yeah, I was tempted by it though after Sakugablog wrote a whole article about it though.