Oscar-nominated ‘Three Billboards Outside Ebbing’ star Sam Rockwell has signed on to lend his voice to a live-action/CG hybrid adaptation of Katherine Applegate’s Newbery Medal-winning 2011 novel ‘The One and Only Ivan.’ Per THR, the book centres on “a silverback gorilla named Ivan (Rockwell) who lives in a cage in a shopping mall along with an elephant named Stella and a stray dog called Bob. Ivan does not remember life before the mall, but when a baby elephant named Ruby enters and Ivan finds himself taking care of her, he begins to rediscover his previous life and concocts a plan to take the baby elephant away from their abusive owner.” Angelina Jolie is on board to voice Stella, with Brooklynn Prince of ‘The Florida Project’ voicing the baby elephant Ruby. Ariana Greenblatt (‘Stuck in the Middle,’ ‘A Bad Moms Christmas’) will play the lead live-action character. Thea Sharrock (‘Me Before You’) is directing, with the script coming from Mike White. In addition to providing her voice, Jolie will also produce the feature alongside Brigham Taylor. Allison Shearmur, who recently passed away, will retain a producer credit on the movie.