Jean Cocteau (1889-1963) was a highly versatile and innovative French poet, novelist, dramatist, film-maker and scriptwriter.
He moved in the most avant-garde of literary and social circles and included amongst his personal acquaintances Marcel Proust, André Gide, Maurice Barrès, Serge Diaghilev, Pablo Picasso, Marlene Dietrich, Coco Chanel and Édith Piaf.
Sergei (often known as Serge) Diaghilev (1872-1929) was a Russian ballet impresario and art critic who founded the Ballets Russes (Russian Ballets), a touring ballet company which performed in Europe and the U.S.A. between 1909 and 1929.
Anthony Blanche being 'on closer terms' with Cocteau and Diaghilev hints at homosexual relationships; Diaghilev was openly homosexual and Cocteau is generally believed to have been homosexual.
Throughout Brideshead Revisited, references to homosexuality are kept vague. It is only very subtly implied that the relationship between Charles Ryder and Sebastian Flyte is a physical one. This may have been due to the sensitivity of the issue in the period in which the novel was written; homosexual acts were illegal under British law until the passing of the Sexual Offences Act in 1967.
Evelyn Waugh's membership of the Roman Catholic Church might also have made him wary of portraying homosexual relationships in his work. Interestingly, however, he clearly had no qualms about his very frank portrayal of Anthony Blanche's homosexuality.