“Harry Potter” director David Yates has come onboard to direct an adaptation of Emma Forrest’s memoir “Your Voice in My Head” for London-based Ruby Films.Ruby, which picked up feature rights to “Voice” earlier this year, made the announcement Wednesday. Forrest, an English novelist, screenwriter and journo based in Los Angeles, is writing the screenplay, which explores the personal crisis she faced when an all-consuming romance fell apart and her psychiatrist died. “Voice” has been developed with funding from the British Film Institute’s Film Fund. Forrest has written the screenplay, set in New York, London and Istanbul, which Alison Owen will produce. Lensing is expected to start next summer. A spokesman for Ruby said the banner is seeking financing for “Voice” from Warner Bros., where Yates directed four of the eight “Potter” films. Warners had no immediate comment. Describing “Voice,” Yates said, “It’s a small film, hard hitting and with elements of magic realism. Compared to ‘Potter’ it would cost tuppency ha’penny, and for that reason it would be incredibly liberating to make.” The helmer told Variety last month that he was developing a “Doctor Who” movie with Jane Tranter, head of L.A.-based BBC Worldwide Prods. (Daily Variety, Nov. 15). Forrest landed on Variety’s Ten Screenwriters to Watch list in 2009 and has written several scripts, including “Liars” and Jeff Buckley biopic “Becoming Music,” optioned by Brad Pitt’s Plan B.