This isn't a new theory, but it's gone somewhat viral in recent weeks, with numerous sites and outlets citing journalist Daniel Loxton's October 2013 article, The Loch Ness Monster's Hollywood Origins.
Basically, Loxton and others have argued, quite persuasively IMO, that the key and classic newspaper reports and images of Nessie - establishing the legendary creature as a long-necked, dinosaur-like beast - may well have been directly inspired by the scene from the original King Kong movie shown above.
Allowing that lake monster legends have existed throughout the world for centuries, it's indisputably true that the early 1930s saw a flap of media reports linking these local legends with dinosaurs. In this article for The Skeptic, for example, Loxton points out that Canada's "Cadborosaurus" monster, known as "Caddy", may also owe its modern origins to the phenomenal cultural impact of King Kong.
Loxton's book on the cultural histories of Nessie, the Yeti and other famous cryptids is available from Amazon and other retailers.