A multiphase pump includes a housing having a pump inlet and a pump outlet for a process fluid, an inlet annulus configured to receive the process fluid from the pump inlet, a discharge annulus configured to discharge the process fluid into the pump outlet, a pump rotor configured to rotate about an axial direction and arranged within the housing, the pump rotor being configured to convey the process fluid from the inlet annulus to the outlet annulus, and a return line configured to return the process fluid from the high pressure side to the low pressure side, the return line including an inlet configured to receive the process fluid, an outlet configured to discharge the process fluid and a control valve configured to open and close the return line, the inlet of the return line arranged directly at the discharge annulus.