The 42-year-old actor will star in Disney's adaptation of the Newbery Medal-winning book, written by Katherine Applegate and illustrated by Patricia Castelao, according to The Hollywood Reporter.
Jolie will voice Stella, a baby elephant who changes Ivan's life - who is a silverback gorilla with a memory lapse - when she enters the mall where he lives.
The actor will also serve as producer on the movie.
Thea Sharrock is attached to direct the film from a script penned by Mike White.
The movie is being said to be a live-action hybrid, which will be co-produced by Allison Shearmur.