The ensemble includes Rachel Zegler, Jonathan Groff, Sheryl Lee Ralph, Phillipa Soo, Gaten Matarazzo, Tramell Tillman and Paul-Jordan Jansen. Rehearsals began after Lin-Manuel Miranda shared an April 14 Instagram post, and Seyfried said the cast has formed a close bond. Dave Malloy, who wrote the original musical, praised Miranda for bringing the piece to life.
Seyfried, who previously starred in Mamma Mia! (2008) and its 2018 sequel, recently played the title in The Testament of Ann Lee (2025) and earned a Golden Globe nomination. Octet does not yet have a release date.