Disclosed herein is a method for preparing a multilayer coating system on a substrate including at least the steps of applying a first coating material composition to a substrate (step (1)), applying a second coating material composition to the first coating film formed in step (1) prior to curing the first coating film and forming a second coating film (step (2)) and jointly curing the first and second coating films (step (3)). Also disclosed herein are a multilayer coating system on a substrate, which is obtainable by the method and a method of using an amino resin (AR) as a migrating crosslinking agent.