an annulus filler assembly for a rotor of a turbomachine , the assembly comprising : an annulus lid having a radially outwardly facing surface for forming an inner wall of a flow annulus of the rotor and a radially inwardly facing surface ; and a frame for supporting the annulus lid , the frame being mountable to a disc of the rotor such that the annulus lid is spaced away from the disc , wherein the frame comprises a connection portion which , in use , passes through an aperture in the annulus lid from the radially inwardly facing surface towards the radially outwardly facing surface such that at least a portion of the connection portion is visible from the radially outwardly facing surface ; the assembly further comprising a locking element which locks the connection portion to the annulus lid via the visible portion of the connection portion .