The Dark Knight star and Blanchett will join British actor Benedict Cumberbatch, who will play villainous tiger Shere Khan, Naomie Harris, Tom Hollander, Eddie Marsan and Peter Mullan in Warner Bros.' adaptation of Rudyard Kipling's adventure tale.
Bale will voice orphan Mowgli's panther friend Bagheera, while Blanchett will play python Kaa, according to The Hollywood Reporter.
Andy Serkis, who will make his directorial debut on the film, will step in as Baloo the bear and Lone Survivor's Rohan Chand will star as Mowgli.
Hollander, Mullan, Harris and Marsan round out the cast as jackal Tabaqui, wolf pack leader Akela, and wolves Nisha and Vihaan, respectively.
This isn't the only The Jungle Book film in the works - Jon Favreau will take charge of a rival Disney live-action/animation production, which features the voices of Idris Elba, Scarlett Johansson, Sir Ben Kingsley, Christopher Walken and Lupita Nyong'o.