An aircraft gas turbine engine (10) comprises a main engine shaft (22, 23), a main engine shaft bearing arrangement (36, 44, 49, 50) configured to rotatably support the main engine shaft (22, 23) and an electric machine (30) comprising a rotor (34) and a stator (32). The rotor (34) is mounted to the main engine shaft (22, 23) and is rotatably supported by the main engine shaft bearing arrangement (36, 44, 49, 50), and the stator (32) is mounted to static structure (46) of the gas turbine engine (10).