Blake Lively (The Shallows) is set to star alongside Anna Kendrick (Twilight Saga) in A Simple Favor, a psychological thriller based on the debut novel by Darcey Bell and adapted for the big screen by Jessica Sharzer (“American Horror Story”) for director Paul Feig.

Slated for release Sept. 14, A Simple Favor stars Lively as a hot milf who is found murdered days after asking her mommy blogger best friend (Kendrick) to pick up her kid from school. Her darkest secrets soon come to light when her friend continues to investigate her death.

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