SEE ALSO: ILLIT praised for making a significant improvement in recent encore live performance

During the showcase, Eunjin had shown signs of breathing troubles, after taking medicine on an empty stomach. According to MBK, "Eunjin left the hospital early in the morning [on April 20]. She is feeling recovered, so she will be able to perform on 'M! Countdown'." 

You'll be able to catch all 9 members of DIA during their comeback stage with "Will You Go Out With Me" on 'M! Countdown'!