The World of Henry Orient (1964)

When Marian Gilbert (Merrie Spaeth) is sent to private school for a better education, she meets rich girl Valarie Campbell Boyd (Tippy Walker), who's full of life. The two quickly become best friends. One night, while attending a piano concert given by Henry Orient (Peter Sellers), Val develops a crush on him, despite his obvious lack of skill on the keyboard.

Val buys his records and a fan magazine that offers a page full of what Orient does all day, from the time he wakes up. The girls decide to camp outside his house and wait for him to start his daily routine. The trouble is that Orient doesn't actually have a daily routine, and the girls crimp his style as he tries to seduce a married woman, Stella Dunnworthy (Paula Prentiss).

Val's overworked imagination, as she writes nonsense about Orient in her diary, leads her usually neglectful mother (Angela Lansbury) to conclude that the pianist is having an affair with her underaged daughter. She goes to see him to set him straight.

Based on the novel by Nora Johnson.