A catalyst system capable of supporting combustion beyond the fuel rich limit of flammability comprising a catalytic component, a first support and a second support and wherein the catalytic component is present on both the first and the second support, and a process for the production of an olefin, said process comprising passing a mixture of a hydrocarbon and an oxygen-containing gas over said catalyst system to produce said olefin. The first support and the second support must differ in at least one of the following aspects: support material, support type and/or structural dimension.