Freddie Highmore, Bill Nighy, Miranda Richardson and Sienna Miller have joined the voice cast of animated “A Fox’s Tale.”Hungary’s George Gat helms from a screenplay he co-wrote with Peter Doka. Pic is produced by Gat for Dyn Ent. and the U.K.’s Bill Chamberlain for Parallel Pictures. International sales rights are being handled by L.A.-based Fantastic Films Intl. Mike Moran is composing the score and songs. Highmore voices a fox called Little Jack, who enjoys a blissful life in the forest until his father, voiced by Phil Davis, is captured and forced to work in the circus.