Abigail Breslin also on board.

Chris Cooper (‘The Company You Keep,’ ‘The Muppets’) and ‘Sherlock’ and ‘Star Trek 2’ star Benedict Cumberbatch are set to join Meryl Streep and Julia Roberts on the cast of the family drama ‘August: Osage County.’

The film is based on the Pulitzer Prize and Tony Award-winning play by Tracy Letts and tells the dark, hilarious and deeply touching story of the strong-willed women of the Weston family, whose lives have diverged until a family crisis brings them back to the Midwest house they grew up in, and to the dysfunctional woman (Streep) who raised them.

Cooper will take the role of Streep’s brother-in-law, Charles Aiken, while THR reports that Cumberbatch will be playing Aiken’s “sensitive son.”

Juliette Lewis is talks to play Karen, the self-deluding youngest daughter. ‘Little Miss Sunshine’ star Abigail Breslin is on board to play Roberts’ 14-year old angry and acerbic pot smoking daughter, Jean Fordham.

Margo Martindale (‘Justified,’ ‘Million Dollar Baby’) will co-star, playing Mattie Fae Aiken, the wife of Charles, and the sister of Violet Weston, played by Streep.

John Wells (‘Company Men’) is directing from a script that Letts penned. The film is expected to go into production next month. George Clooney and his Smokehouse Pictures partner Grant Heslov are producing.