Process for the preparation of a composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc, wherein the heterophasic propylene copolymer consists of (a) a propylene-based matrix wherein the propylene-based matrix consists of a propylene homopolymer and/or a propylene-α-olefin copolymer consisting of at least 70% by mass of propylene and up to 30% by mass of α-olefin, based on the total mass of the propylene-based matrix wherein the α-olefin in the propylene-α-olefin copolymer is selected from the group of α-olefins having 2 or 4-10 carbon atoms, wherein the propylene-based matrix is present in an amount of 60 to 95wt% based on the total heterophasic propylene copolymer and (b) a dispersed ethylene-α-olefin copolymer, wherein the amount of ethylene in the ethylene-α-olefin copolymer is in the range of 20-65wt%, wherein the α-olefin in the ethylene-α-olefin copolymer is chosen from the group of α-olefins having 3 to 8 carbon atoms and any mixtures thereof, wherein the dispersed ethylene-α-olefin copolymer is present in an amount of 40 to 5wt% based on the total heterophasic propylene copolymer and wherein the sum of the total amount of propylene-based matrix and total amount of the dispersed ethylene-α-olefin copolymer in the heterophasic propylene copolymer is 100wt% wherein the composition has a desired melt flow index in the range of 1 to 200dg/min as measured according to ISO1133 (2.16 kg/230°C) comprising the steps of (a) melt-mixing a propylene copolymer with a talc to obtain a masterbatch (b) melt-mixing the masterbatch with the heterophasic propylene copolymer and a peroxide to obtain the composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc, wherein the amount of peroxide is chosen such that a composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc having the desired melt flow index is obtained, wherein at least part of the talc in the composition is surface modified and wherein the amount of talc in the composition is from 0.5 to 5wt% based on the total amount of the propylene copolymer of step a) and the heterophasic propylene copolymer of step b). (a) a propylene-based matrix wherein the propylene-based matrix consists of a propylene homopolymer and/or a propylene-α-olefin copolymer consisting of at least 70% by mass of propylene and up to 30% by mass of α-olefin, based on the total mass of the propylene-based matrix wherein the α-olefin in the propylene-α-olefin copolymer is selected from the group of α-olefins having 2 or 4-10 carbon atoms, wherein the propylene-based matrix is present in an amount of 60 to 95wt% based on the total heterophasic propylene copolymer and (b) a dispersed ethylene-α-olefin copolymer, (a) melt-mixing a propylene copolymer with a talc to obtain a masterbatch (b) melt-mixing the masterbatch with the heterophasic propylene copolymer and a peroxide to obtain the composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc, wherein the amount of peroxide is chosen such that a composition comprising a heterophasic propylene copolymer, a propylene copolymer and talc having the desired melt flow index is obtained,