Star joins film adaptation.

Variety has learned that Ewan McGregor (‘Salmon Fishing in the Yemen,’ ‘Beginners’) has signed on to join Julia Roberts and Meryl Streep on the cast of the John Wells-directed family drama ‘August: Osage County.’

A feature adaptation of the Pulitzer Prize and Tony Award-winning play by Tracy Letts, ‘August: Osage County’ tells the dark, hilarious and deeply touching story of the strong-willed women of the Weston family as a crisis brings them back to their Midwest home.McGregor will be playing the estranged husband of Roberts’ character, a college professor who left his wife for a student.

The cast also includes Chris Cooper (‘The Company You Keep’), Benedict Cumberbatch (‘Star Trek 2’), Juliette Lewis (‘Due Date’), Abigail Breslin (‘Little Miss Sunshine’), Dermot Mulroney (‘Jobs’), Sam Shepard (‘Out of the Furnace’) and Margo Martindale (‘Justified,’ ‘Million Dollar Baby’).

McGregor will next be seen starring opposite Naomi Watts in Juan Antonio Bayona’s tsunami drama ‘The Impossible’ when it opens in Irish cinemas January 2013.