Rena Matsui is a Japanese actress, singer, and novelist. Matsui is a former member of the Japanese idol girl groups SKE48 and Nogizaka46. As a member of the former, she also participated in the main lineup of AKB48's singles. As an actress, she has played roles in numerous films and television series, including Kamen Rider Build the Movie: Be the One and the 99th NHK asadora Manpuku.

SKE48 is a Japanese idol group produced by Yasushi Akimoto. SKE48 is named after the Sakae district in Nagoya of Aichi Prefecture, where the group is based. The group performs at SKE48 Theater on 2F of Sunshine Sakae, a shopping center in Sakae, Nagoya. Avex Group is its current official label. The group has sold nearly 11 million CDs in Japan.