An Al-steel assembly is provided. The assembly includes an aluminum-based element and a steel element on at least one surface of the aluminum-based element. The steel element has a metal coating made of a zinc-aluminum-magnesium alloy and includes from 2.3% to 3.3% by weight of magnesium and from 3.6% to 3.9% by weight of aluminum. A coated surface of the steel element is in contact with the aluminum-based element in an assembly zone and a protective coating coats the assembly around and adjacent the assembly zone. A body-in-white, further assembly and method are also provided.