Chris Cooper is in negotiations to join the cast of the Weinstein’s Co.’s “August: Osage County,” joining leads Meryl Streep and Julia Roberts.

Pic is an adaptation of Tracy Letts’ play with John Wells helming from a script that Letts penned.

Story revolves around the Weston family, whose members have to overcome certain differences when their alcoholic patriarch goes missing. Cooper will play Streep’s brother-in-law.

Jean Doumanian and Harvey Weinstein will produce. Plan is to go into production sometime in August.

The casting marks a reteaming with Cooper and Wells, who worked together on Wells’ directing debut “Company Men.”

The Paradigm- and Untitled Entertainment-repped Cooper can be seen next in “The Company That I Keep.”