A seal assembly comprising: first, second, and third gas turbine engine components that are successively arranged around an axis, each of the first, second, and third gas turbine engine components being a vane assembly having a first and a second platform (66, 68) between which an airfoil section extends, the first platform having first and second mate faces such that the first mate face of the first gas turbine engine component is adjacent to the second mate face of the second gas turbine engine component to define a first mate face gap therebetween and the first mate face of the second gas turbine engine component is adjacent to the second mate face of the third gas turbine engine component to define a second mate face gap therebetween; and a seal arc segment arranged around the axis, the seal arc segment having first and second seal portions that are circumferentially spaced-apart and a connector portion joining the first and second seal portions, the seal arc segment being arranged such that the first seal portion bridges the first mate face gap to seal the first mate face gap, the second seal portion bridges the second mate face gap to seal the second mate face gap, and the connector portion spans circumferentially across the second gas turbine engine component, characterised in that the seal assembly further comprises two brush seals extending from support hardware and contacting a radially outer surface of the seal arc segment at a leading end of the seal arc segment and at a trailing end of the seal arc segment to thereby isolate a cooling air zone, wherein the cooling air zone is configured to use air to cool the region of a leading edge of the airfoil section, wherein the brush seals seal against the radially outer surface of the seal arc segment. first, second, and third gas turbine engine components that are successively arranged around an axis, each of the first, second, and third gas turbine engine components being a vane assembly having a first and a second platform (66, 68) between which an airfoil section extends, the first platform having first and second mate faces such that the first mate face of the first gas turbine engine component is adjacent to the second mate face of the second gas turbine engine component to define a first mate face gap therebetween and the first mate face of the second gas turbine engine component is adjacent to the second mate face of the third gas turbine engine component to define a second mate face gap therebetween; and a seal arc segment arranged around the axis, the seal arc segment having first and second seal portions that are circumferentially spaced-apart and a connector portion joining the first and second seal portions, the seal arc segment being arranged such that the first seal portion bridges the first mate face gap to seal the first mate face gap, the second seal portion bridges the second mate face gap to seal the second mate face gap, and the connector portion spans circumferentially across the second gas turbine engine component, characterised in that the seal assembly further comprises two brush seals extending from support hardware and contacting a radially outer surface of the seal arc segment at a leading end of the seal arc segment and at a trailing end of the seal arc segment to thereby isolate a cooling air zone, wherein the cooling air zone is configured to use air to cool the region of a leading edge of the airfoil section, wherein the brush seals seal against the radially outer surface of the seal arc segment.