From The Hollywood Reporter:
Universal Pictures and Jason Blum’s Blumhouse Productions are joining forces on the fantasy-horror tale Mercy, an adaptation of Stephen King’s short story Gramma.
British actress Frances O’Connor will star in the project, to be directed by Peter Cornwell from a script by Matt Greenberg. Blum will produce with Wonderland Sound and Vision’s McG andMary Viola.
The tale, which King first published in 1984 in Wierdbook magazine and which was then published in his 1985 short story collectionSkeleton Key, concerns a mother, played by O’Connor, with two young sons who come to discover their ailing grandmother, Mercy, is a witch.
We've heard most of this before, including some new info that Dylan McDermott will also be in the film.