Do you know any movie or a book, that has doppelganger in it? or just a person that looks the same who takes the main character's place?
These aren't exactly what you've described, but similar and very very good:Single White FemaleThe Talented Mr. RipleyPacific Heights
The thing. Don't forget X-Men.
"Dave", a presidential impersonator takes his place when the real president has a heart attack.
There is a 1993 movie called Doppelg?nger. Never saw it, so really cannot tell you about it.
Wild Wild WestThe Sixth Day