TheWater Horse: Legend of the Deep is a 2007 fantasy film directed by Jay Russell. The screenplay, written by screenwriter Robert Nelson Jacobs, is an adaptation of Dick King-Smith’s children's novel The Water Horse. It stars Alex Etel as a young boy who discovers a mysterious egg and cares for what hatches out of it: a 'water horse' (loosely based on the Celtic water horse) which later become the fabled Loch Ness Monster, Emily Watson, Ben Chaplin, and David Morrissey.