A concentric cam shaft assembly, including: a first camshaft; a second camshaft including at least a portion disposed radially within the first camshaft; and at least one phasing assembly including first and second electric motors and a first input gear arranged to rotate at a first speed in response to receiving rotational torque from a crankshaft of an engine. The rotational torque is arranged to rotate the first and second camshafts. The first electric motor is arranged to circumferentially off-set the first camshaft with respect to the first input gear. The second electric motor is arranged to circumferentially off-set the second camshaft with respect to the first input gear.