The Water Horse: Legend of the Deep (known on-screen as simply The Water Horse) is a 2007 American-British family fantasy drama film directed by Jay Russell. The screenplay, written by 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 becomes the fabled Loch Ness Monster. The film also stars Emily Watson, Ben Chaplin, and David Morrissey.
The film was produced by Revolution Studios and Walden Media, in collaboration with Beacon Pictures, and was distributed by Columbia Pictures. Visual effects, which included the computer-generated imagery of the water horse (named "Crusoe" by Etel's character) were completed by the New Zealand-based companies Weta Digital and Weta Workshop—visual effects companies who worked with Walden Media before on the productions of The Chronicles of Narnia films.