The present technique presents a gas turbine blade for re-using cooling air, a turbomachine assembly having the blade, and a gas turbine having the turbomachine assembly. The blade includes a platform and an airfoil extending from the platform. The airfoil includes a pressure surface, a suction surface, a leading edge and a trailing edge. The platform includes a pressure side, a suction side, a leading-edge side and a trailing-edge side, disposed towards the pressure surface, the suction surface, the leading edge and the trailing edge of the airfoil, respectively. The suction side of the platform includes a part of the upper surface and a suction-side lateral surface of the platform. At least a part of an edge between the suction-side lateral surface and the upper surface of the platform comprises a chamfer part.