So i am searching for this color English movie with a raw diamond. The museum hires a thief to check there security system and the police officer disagree. Then the thief disguises as the man who is going to cut the diamond so he can steal it! He also fall in love with the librarian girl and flirt with her as a thief and as the man he disguised into. In the end he takes the diamond but the police officer was the one who asked it and he gave it to him but it was the fake one.