In a hydraulic camshaft adjuster for a camshaft of an internal combustion engine and a method of assembling the camshaft adjuster including an inner body, which is connected to the camshaft in a rotationally fixed manner and has outwardly extending blades and an outer body which has inwardly projecting blades which form, together with the outwardly extending blades, at least one hydraulic medium chamber between two housing side covers connected to the outer body and operatively connected to a crankshaft of an engine so as to be driven thereby, a locking bolt is provided for locking the inner body in relation to the outer body with a predetermined play.