An airfoil assembly for a gas turbine engine, the airfoil assembly comprising: a first airfoil having a first platform (122a, 222), the first platform having a first mating surface (144, 244) and a second mating surface (146, 246), wherein the first platform defines a first channel (160, 260) having an outlet (162, 262) formed in the second mating surface; and a second airfoil adjacent to the first airfoil, the second airfoil having a second platform (122b, 222) with a first mating surface (144, 244) and a second mating surface (146, 246), wherein the first channel (160a, 260) in the first airfoil is configured to deliver a cooling airflow to the first mating surface of the second airfoil; wherein the first platform includes a pocket defined in an inner diameter surface of the first platform proximate the first mating surface of the first platform, and wherein an inlet of the first channel is defined in the pocket; or wherein the first airfoil further comprises a root disposed radially inward of the first platform, and wherein an inlet of the first channel is defined in a first circumferential side of the root proximate the first mating surface of the first airfoil; the airfoil assembly being characterised in that the first platform (122a, 222) defines a second channel (160b, 260) having an inlet (166, 266), and further having an outlet (162, 262) formed in the second mating surface (146, 246), and wherein the first channel (160a, 260) is formed in a plane which is different than a plane in which the second channel (160b, 260) is formed, such that inlets (166, 266) of the first and the second channels (160a, 160b) are defined at different radial, axial and circumferential locations. a first airfoil having a first platform (122a, 222), the first platform having a first mating surface (144, 244) and a second mating surface (146, 246), wherein the first platform defines a first channel (160, 260) having an outlet (162, 262) formed in the second mating surface; and a second airfoil adjacent to the first airfoil, the second airfoil having a second platform (122b, 222) with a first mating surface (144, 244) and a second mating surface (146, 246), wherein the first channel (160a, 260) in the first airfoil is configured to deliver a cooling airflow to the first mating surface of the second airfoil; wherein the first platform includes a pocket defined in an inner diameter surface of the first platform proximate the first mating surface of the first platform, and wherein an inlet of the first channel is defined in the pocket; or wherein the first airfoil further comprises a root disposed radially inward of the first platform, and wherein an inlet of the first channel is defined in a first circumferential side of the root proximate the first mating surface of the first airfoil; the airfoil assembly being characterised in that the first platform (122a, 222) defines a second channel (160b, 260) having an inlet (166, 266), and further having an outlet (162, 262) formed in the second mating surface (146, 246), and wherein the first channel (160a, 260) is formed in a plane which is different than a plane in which the second channel (160b, 260) is formed, such that inlets (166, 266) of the first and the second channels (160a, 160b) are defined at different radial, axial and circumferential locations.