Google's AI has nothing I could find on the above story, but does report this:
"Katharine Hepburn and Stephen Sondheim: The legendary actress and composer lived next door to each other for years in the exclusive Turtle Bay Gardens on Manhattan's East Side. However, they were not on good terms. Hepburn, known for her privacy, reportedly complained about noise from Sondheim's piano playing. Some anecdotal accounts suggest their feuding inspired the song "It's the Witch from Next Door" in Sondheim's musical Into the Woods."