He will make his onscreen debut in the title role.
Denchs casting had previously beenreported.
Shell play Commander Root, the steely leader of the fairy police force.
Credit: Matt Winkelmeyer/Getty Images; Steve Mack/FilmMagic; Jun Sato/WireImage
Gad will star as Mulch Diggums, a kleptomaniacal dwarf who works for the fairies (and himself).
The upcoming film is based on the wildly successful sci-fi book series by Eoin Colfer.
Branagh most recently directedMurder on the Orient Express, which both Dench and Gad starred in.
Artemis Fowlwill hit theaters on August 9, 2019.
Production begins early next year in the U.K.
