The 22-year-old actress has joined the cast of the coming-of-age romance drama, which is based on the Krystal Sutherland novel Our Chemical Hearts, The Hollywood Reporter confirmed Friday.
Reinhart will play Grace Town, a high school senior who meets protagonist Henry Page after transferring to his school. The movie follows the romance between Grace and Henry, who has never been in love.
Southside with You director Richard Tanne will helm the film and co-produce with Alex Saks. Reinhart and Jamin O'Brien will serve as executive producers.
Deadline said production on Chemical Hearts is underway in New Jersey. The movie is an Amazon Original and will premiere on Amazon Prime Video.
"We are thrilled to work with this talented team to bring to life a beautiful story of first love and heartbreak," Amazon Studios co-head of movies Julie Rapaport said. "Krystal Sutherland's novel captured the hearts of readers around the world, and we are excited to bring this film to our global Prime Video customers."
Reinhart is best known for playing Betty Cooper on The CW series Riverdale. The show co-stars KJ Apa, Camila Mendes and Cole Sprouse, and was renewed for a fourth season in January.