Mechanical control systems are an especially interesting and important class of nonlinear control systems. They posses a rich mathematical structure and yet, physical considerations reveal extremely important for the solution of a large class of control problems. In this note, we broaden the applicability of design methodologies developed for mechanical control systems by rendering nonlinear control systems, mechanical by a proper choice of feedback. In particular, we characterize which control systems can be transformed to Hamiltonian control systems by a feedback transformation.