CANNES — Cobalt Media Group has boarded John Boorman’s fantasy kidpic “Knight’s Castle.”

Pic, which starts shooting in August in Ireland, is scripted by Tony Grisoni from a book by Edward Eager. No cast is yet attached.

It’s an adventure story about a 10-year-old boy who is magically transported back to medieval times, where he must rescue the mythical sword Excalibur in order to heal both the king and his own sick father back in the present.

“It’s a classic quest story in which an ordinary boy is chosen for a great life-or-death mission — scary but not too frightening, and with a lot of wit to keep the adults in the audience amused,” Boorman said.

The film is produced by Boorman’s own Merlin Films, with Kieran Corrigan as exec producer.

“John Boorman is a master of the genre, with ‘Excalibur’ one of the best fantasy films ever made,” said Cobalt’s Peter Rogers. “He has also shown, with ‘Hope and Glory,’ for instance, that he knows how to get great performances from child actors.”