A camshaft adjuster (1) for driving and/or adjusting a camshaft (2) of an internal combustion engine, including a stator (3) and a concentric rotor (6) which is arranged within the stator in a rotatable manner. At least the stator (3) has a central receiving area (31) for receiving the camshaft (2), and at least one projection (13) which protrudes radially inwards is provided on a radial inner edge (12) of the central receiving area (31) in order to engage behind a camshaft (2) connecting piece (20) which protrudes radially outwards. A camshaft adjuster/camshaft combination (26) including such a camshaft adjuster (1) and a camshaft (2) which has a connecting piece (20) that projects radially. The projection (13) preferably engages behind the connecting piece (20). A method for assembling the camshaft adjuster/camshaft combination (26) is also provided.