My Sister’s Boyfriend Film Teaser Adds Two Cast Members

The live-action My Sister’s Boyfriend film introduced additional cast members through a new teaser trailer and poster. Rinka Kumada joins as Momo Sanae, the older sister of heroine Sui and girlfriend of Midori, while Reo Matsumoto plays Sui’s childhood friend Ayame Mizukawa. The film stars Masaki Hashimoto as Midori Yukishiro and Runa Nakajima as Sui Sanae. Its story follows a junior high student who dislikes her older sister’s boyfriend because he treats her like a child, only to discover another side of him after he becomes her home tutor. Mahito Kimura directs from a screenplay by Nami Kikkawa, with Shochiku overseeing and distributing the production. The film opens in Japan on December 4, 2026.

Anime News Network, Rafael Antonio Pineda – Live-Action My Sister’s Boyfriend Film’s Teaser Announces More Cast – 4th August 2026