Evelyn Waugh was born in 1903; Katharine Houghton Hepburn, four years later. Of Waugh's novels that were adapted to film, Hepburn appeared in but one: Love Among the Ruins.
Hepburn's co-star in Love Among the Ruins, Laurence Olivier, starred also in a mini-series based on Waugh's Brideshead Revisited...
...which co-starred, among others, Jeremy Irons of The Merchant of Venice (2004).
Merchant featured Allan Corduner, a.k.a. Sir Arthur Sullivan of Topsy-Turvy, the co-star of which (Jim Broadbent as W.S. Gilbert) was in Widow's Peak with Natasha Richardson...
...whose mother (and co-star in The White Countess), Vanessa Redgrave, appeared in the play A Madhouse in Goa with Rupert Graves.
And Graves starred in the film adaptation of Waugh's A Handful of Dust.