Top hat top hat is a hard, black silk hat, with fur now often used. The acceptable colors of hats are much as they have traditionally been, with "white" hats (which are actually grey), a daytime racing color, worn at the less formal occasions demanding a top hat, such as Royal Ascot, or with a morning suit. In the U.S. top hats are worn widely in coaching, a driven horse discipline as well as for formal riding to hounds. The collapsible silk opera hat, or "crush hat", is still worn on occasions, and black in color if worn with evening wear as
Top Hat as early as 1915. There ensued a lifelong friendship with Berlin contributing to more Astaire films (six in total) than any other composer. Of his experience with Astaire in "Top Hat" Berlin wrote: "He's a real inspiration for a writer. I'd never have written "Top Hat" without him. He makes you feel so secure." As Berlin could not read or write music, and could only pick out tunes on a specially designed piano that transposed keys automatically, he required an assistant to make up his piano parts. Hal Borne – Astaire's rehearsal pianist – performed this role in "Top Hat"