Harvey (1950)

The classic stage hit gets the Hollywood treatment in the story of Elwood P. Dowd who makes friends with a spirit taking the form of a human-sized rabbit named Harvey that only he sees (and a few privileged others on occasion also.) After his sister tries to commit him to a mental institution, a comedy of errors ensues. Elwood and Harvey become the catalysts for a family mending its wounds and for romance blossoming in unexpected places.