This invention relates to an aqueous coating composition, a greaseproof article and a process of forming a coating on a substrate. The aqueous coating composition comprises at least the following components: an organopolysiloxane (A) which is a polysiloxane compound having at least two alkenyl groups per molecule, an organohydrogenpolysiloxane (B) which is a polysiloxane compound comprising at least two Si H groups per molecule, an hydrosilylation catalyst (C) able to catalyse an hydrosilylation reaction between the organopolysiloxane compound (A) and the organohydrogenpolysiloxane compound (B), an organic copolymer (D) comprising at least two types of repeating units (i) and (ii): unit (i) which is an alkyl group comprising from 2 to 2 carbon atoms, unit (ii) which is an alkyl group comprising from 2 to 12 carbon atoms and having at least one pendant alcohol substituent, water, and the composition is able to form upon curing by hydrosilylation a coating on a substrate.