Sienna Miller Joins Bennett Miller's 'Foxcatcher' With Steve Carell, Mark Ruffalo & Channing Tatum

While it seems the big and pieces for this one have been coming together forever, we're just glad Bennett Miller's "Foxcatcher" is still happening. And after lining up an impressive trio of bros in Steve Carell, Channing Tatum and Mark Ruffalo, the film is now adding a talented actress into the mix.

Sienna Miller has come aboard the film that will once again find the director of "Capote" and "Moneyball" tackling a true-life story, although something far stranger than both of those films. Penned by E. Max Frye and Dan Futterman ("Capote") the story centers on John du Pont (Carell), a stamp-collecting, bird-watching multimillionaire and paranoid schizophrenic who built a wrestling training facility, Team Foxcatcher, on his 800-acre Pennsylvania estate. In 1996, he shockingly murdered Olympic gold medal-winning wrestler David Schultz (Ruffalo), a longtime friend, who du Pont believed (as was discovered during the trial) was part of an international conspiracy to kill him. Miller and Tatum will play Schultz's wife and brother, respectively.

We're pretty excited for this one for a number reasons, not least being the cast. We're really curious to see what Carrell does with the material, while Ruffalo is always solid, and Tatum continues to make some fascinating choices. As for Miller, this writer feels she's always been underrated and perhaps plagued by movies that never quite turn out the way they should have. But she'll get another another chance to shine in the Hitchcock tale "The Girl" set to air on HBO later this month.

Production begins on "Foxcatcher" in Pittsburgh later this month. [Deadline]