Abstract: The invention relates to a method for the preparation of a hybrid nano-structured composite comprising cellulose nano-particles and metal compound nano-particles, to the nano structured-composite product obtainable by the process and to uses thereof. The method comprises the steps of contacting virgin cellulose with a molten metal salt solvent M1-S and dissoluting the virgin cellulose, optionally exchanging at least part of metal ions M1 with metal ions M2 and converting at least part of the metal ions M1 and/or optional M2 to metal compound nano-particles, precipitating the cellulose nano-particles and isolating the co-precipitated cellulose- and metal compound nano-particles.