An electric machine assembly including a body part; a stator stationarily supported to the body part; a rotor adapted to rotate relative to the stator, and adapted to receive a shaft inside thereof; and a locking system for providing a locking state for the electric machine assembly in which the rotor is locked relative to the stator. The locking system includes at least one locking member adapted to be in a separating position between the rotor and the stator; and a plurality of radial bolt holes provided in the rotor, extending in a radial direction, and adapted to receive centring bolts such that distal ends of the centring bolts press the at least one locking member in the separating position radially outwards relative to the rotor.