The group is currently composed of seven members: Jiyoon, E.Ji, Jackie, Joonie, Chaerin, Yeju and Chowon.

[3] The official fan club name of Ichillin' is "Willing", which was announced on December 10, 2021 after a poll between 7 candidates that each of the members have picked.

[4] Ichillin' was to debut on August 25, 2021, but it was delayed in order to show more completeness in the group through improvements on the album.

The group then followed up promotions for "Play Hide & Seek" with one of the EP's tracks "La Luna", beginning June 11 the same year.

[8] On July 15, KM Entertainment announced that Sohee would be leaving the group, after discussions between the two parties.