Hinata to Hikari

Hinata, who is an ordinary middle school girl from every angle, is the twin sister of the popular idol Hikari! In order not to disappoint Hikari's fans, Hinata has always kept her sister a secret and behaved in a low-key manner. One day, in order to save Hikari from a pinch, Hinata switches places with Hikari and jumps into a glittering world!!

(Source: Kodansha, translated)