The UK star joins the Blue Dream Studios animation as the voice of Zoe Huntington alongside husband John Krasinksi.
Animal Crackers will also feature the previously attached Danny DeVito, Sylvester Stallone and Ian McKellen.
Krasinksi will play Blunt’s on-screen husband Owen Huntington, who along with his wife inherits a ramshackle circus and a mysterious box of Animal Crackers biscuits that turns people who eat them into animals.
Scott Christian Sava and Tony Bancroft co-direct and Sava co-wrote the script with Dean Lorey. The project is scheduled for completion in summer 2016.
“When Emily and John came in and performed their first scenes of the movie together… it was magic,” said Sava.
“I can think of no other way of describing what they brought to the film. We had to literally go back and re-storyboard the sequences because they took us to places we never dreamed. Owen and Zoe came to life when Emily and John spoke”
Sava produces for Blue Dream Studios alongside George Lee and Marcus Englefield of Storyoscopic Films, Jamie Thomason and Leiming Guan.