I Was Monty's Double

I Was Monty's Double (released in the US as The Counterfeit General Montgomery) is a book by M. E. Clifton James, first published in London in 1954. It was made into a film in 1958, directed by John Guillermin, from a screenplay adapted by Bryan Forbes. It tells the story of Operation Copperhead: James had an uncanny resemblance to General Montgomery in real life, and he was used to impersonate Montgomery to confuse the Germans during the Second World War.