Annulus filler for a rotor disk of a gas turbine

An annulus filler is provided for mounting to a rotor disc of a gas turbine engine and for bridging the gap between two adjacent blades attached to the rotor disc. The annulus filler has a body portion which defines an airflow surface for air being drawn through the engine. The annulus filler further has a front attachment formation which connects a forward end of the body portion to the rotor disc and which allows rotational movement of the body portion thereabout. The annulus filler further has a rear attachment formation which connects a rearward end of the body portion to the rotor disc. The rear attachment formation comprises a spring element which extends between the body portion and the rotor disc. The spring element expands under operational centrifugal loading such that the rearward end of the body portion moves radially outwardly with the body portion rotating about the front attachment formation.