Looker.

An unraveling woman, unhappily childless and recently separated, becomes fixated on her neighbor--the beautiful, famous actress. The unnamed narrator can't help noticing with wry irony that, though she and the actress live just a few doors apart, they are separated by a chasm of professional success and personal fulfillment. When an interaction with the actress at the annual block party takes a disastrous turn, what began as an innocent preoccupation spirals quickly, and lethally, into a frightening and irretrievable madness.