John Malkovich joins Secretariat cast
Malkovich is set to play a charismatic trainer who underestimates the power of Secretariat and Glenn will fill the role of a southern-bred aristocrat who loses the horse in a coin toss, reports The Hollywood Reporter.
Meanwhile, Walsh will form an on-screen partnership with Diane Lane, who will play the horse's owner Penny Tweedy famous for breaking through the gender barrier.
Filming on the picture is expected to commence this week at locations in Louisiana and Kentucky.
Malkovich has been nominated for two Oscars during his career for his roles in In the Line of Fire and Places in the Heart.
He has recently finished filming Jonah Hex, a thriller set in the Wild West about a scarred bounty hunter who tracks a voodoo practitioner bent on liberating the South by raising an army of the undead.