A gas turbine engine includes a diffuser section supplying cooling fluid, a rotatable shaft, shaft cover structure disposed about the rotatable shaft, support structure, and a cooling fluid channel between the shaft cover structure and the support structure. The support structure provides structural support for the shaft cover structure and receives cooling fluid from the diffuser section. One of the diffuser section and the support structure comprises a plurality of apertures through which at least a portion of the cooling fluid passes. The cooling fluid channel is in fluid communication with the apertures in the one of the diffuser section and the support structure for supplying cooling fluid to a blade disc structure located in a turbine section of the engine.