Crunchyroll has announced that an OVA for the TONIKAWA: Over The Moon For You anime is coming to the service in 2021. More details about the OVA will be forthcoming at a later date.
Crunchyroll describes the story of TONIKAWA: Over The Moon For You as:
Nasa Yuzaki falls in love at first sight after an encounter with the mysterious Tsukasa. When Nasa earnestly confesses his feelings, she replies, “I’ll date you, but only if we’re married.” Nasa and Tsukasa’s cute and precious newlywed life of love is about to begin.