Abstract: A gas turbine which includes a compressor, a combustion chamber, a turbine inlet, and at least one turbine as well as a diffusor disposed at an outlet of the gas turbine. An external metallic supporting housing is provided with wall parts for enclosing the combustion chamber, the turbine inlet, and the diffusor. At least the wall parts in a vicinity of the combustion chamber are provided with a heat-insulating inner lining. The heat-insulating inner lining includes a gas-permeable porous material disposed at a distance from the wall parts of the housing so as to define an air distribution space which is sealed from the exterior. The air distribution space is adapted to be connected with an air source.