Based on Osamu Tezuka's manga creation, which was serialised on television in the 1960s, 1980s and again in 2003, Astro Boy centres on a young robot's odyssey to gain acceptance in the eyes of his creator.
Highmore currently stars in the top 10 North American release The Spiderwick Chronicles and rose to prominence with roles in Finding Neverland and Charlie And The Chocolate Factory.
David Bowers, who directed Flushed Away, is directing the film which has been earmarked for a 2009 worldwide release. Warner Bros and The Weinstein Company hold North American rights.
'I am very thrilled that Freddie has accepted this role,' producer Maryann Garger said. 'He is one of the most talented and acclaimed young actors today, and absolutely ideal to portray the iconic Astro Boy.'
Imagi's first theatrical release TMNT launched at number one in North America in March 2007 through Warner Bros.