Ayumu Sensei to Hikaru-kun

Ayumu, a nursery teacher, finds a suspicious person at the nursery school where he works. However, the suspicious person turns out to be a popular actor named Hikaru Momose. Ayumu used to be a tutor for Hikaru, and they had promised to get married if Hikaru's feelings doesn't change even after he becomes an adult?!

(Source: Kadokawa, translated)

Note: Chapter count includes an extra.