Michael Caine and Jennifer Garner have joined the cast of Imagine.
The film centers around an aging rock star, played by Al Pacino, who discovers an unopened letter from John Lennon.
Upon reading the letter, he learns that he has an adult son that he never knew about.
Annette Bening and Bobby Cannavale are also set to star.
Dan Fogelman wrote the script, and will make his directorial debut with the film.