How to Kill Your Neighbor's Dog (2000)

The film stars Kenneth Branagh as Peter McGowan, a chain-smoking, impotent, insomniac playwright who lives in Los Angeles. Once very successful, he is now in the tenth year of a decade-long string of production failures. His latest play is in the hands of effeminate director Brian Sellars (David Krumholtz), who is obsessed with Petula Clark; his wife Melanie (Robin Wright Penn) is determined to have a baby; he finds himself bonding with a new neighbor's lonely young daughter (Suzi Hofrichter) who has mild cerebral palsy; and during one of his middle-of-the-night strolls, he encounters his oddball doppelgänger (Jared Harris) who claims to be Peter McGowan and develops a friendship of sorts with him.