It was released through RBW and Kakao Entertainment on October 11, 2022, as the lead single from their twelfth extended play Mic On.
[2] It was co-written by Moonbyul, Yoo Joo-yi, Kang Ji-won, Kim Do-hoon, and Inner Child, the latter three of whom also handled the song's production.
[6] Divyansha Dongre of Rolling Stone India described it as a reggaeton track that beautifully fuses rich brass sounds with guitar riffs.
They further commented "It’s a near-perfect soundscape to underline Mamamoo’s vocal prowess that has helped cement their identity as one of K-pop’s leading girl groups".
[7] Writing for Billboard, Jeff Benjamin said “Illella” is a full-fledged reminder of their commanding vocal deliveries and artistic auras, that serves powerful belts and sleek harmonies".