Midnight Diner (2009)

S3E24 Diary of a Mad Millionaire

A wealthy introvert who admires the Partridge family hires them to give a private performance at his mansion. He becomes infatuated with their music, attending every concert they have. Eventually, they invite him to join them, hoping he can maintain a low-key presence. However, his attempts to blend in lead to some amusing situations as he navigates life with the family.