The production of lightweight closure assemblies with a selection of materials optimized to have sufficient formability for each component of the closure assembly, while providing the necessary performance standards at a lighter weight. A mixed metal vehicle closure assembly with an inner panel and an outer panel operatively connected to one another such that they define a cavity therebetween. The closure assembly includes a unitary reinforcement panel attached to the inner and outer panels and inside the cavity therebetween. At least one of the inner, outer and unitary reinforcement panels is composed of a first type of sheet metal and at least one other of the remaining inner, outer or unitary reinforcement panel is composed of a second type of sheet metal.