A spindle drive assembly for opening and/or closing a vehicle hatch is described. This comprises a spindle extending along a spindle drive axis and a spindle drive motor coupled to the spindle in terms of drive, the motor shaft of which is arranged substantially coaxially with respect to the spindle drive axis. The spindle drive motor is coupled to the spindle via a two-stage epicyclic gearing. Furthermore, a vehicle hatch with such a spindle drive assembly is presented. A method for installing an epicyclic gearing of such a spindle drive assembly is additionally specified.