The present invention relates to process for the production of a coated substrate comprising cellulosic fibres, the process comprising the steps of: i) providing a first substrate comprising cellulosic fibres and having a dry content of less than 50%; ii) applying a coating composition to the first substrate in an amount of more than 5 g/m2, calculated as dry weight of the coating composition, wherein the coating composition comprises: microfibrillated cellulose (MFC), and optionally a water retention agent selected from carboxymethyl cellulose (CMC), anionic polyacrylamide (A-PAM), sodium polyacrylates, polyacrylic acid derivatives, guar gum, alginate, MFC prepared from carboxymethylated fibers, MFC prepared from oxidized fibers, MFC prepared by CMC-functionalised fibers, and/or combinations thereof; and iii) mechanically dewatering the first substrate. The present process provides an energy efficient coating process which can be performed online.