A gas turbine engine comprising: a combustor shell comprising a diffuser-facing side and a combustor-facing side; and a combustor panel comprising an attachment feature having a central longitudinal axis and extending from a cold side of the combustor panel, the attachment feature comprising a tip portion and a base portion, wherein the attachment feature is configured to extend through the combustor shell such that the tip portion is disposed outward of a diffuser-facing side of the combustor shell, wherein the base portion is configured to be disposed between the cold side of the combustor panel and the diffuser-facing side of the combustor shell; wherein the combustor panel is coupled to the combustor shell via the attachment feature, the attachment feature extending through a hole in the combustor shell, wherein an annular cooling cavity is defined between the combustor shell and the combustor panel; and wherein the attachment feature defines a core passage extending from an inlet opening for receiving cooling air from a diffuser chamber that is at least partially defined by the diffuser-facing side of the combustor shell, the inlet opening defined on the tip portion and extending partially through the attachment feature to terminate within the attachment feature, and an offshoot passage extending from the core passage to an outlet opening for delivering the cooling air to the annular cooling cavity adjacent the attachment feature, the outlet opening defined on the base portion, the core passage and the offshoot passage collectively forming a cooling airflow conduit which extends through the attachment feature; characterised in that: the outlet opening of the offshoot passage is at least partially disposed within the hole in the combustor shell. a combustor shell comprising a diffuser-facing side and a combustor-facing side; and a combustor panel comprising an attachment feature having a central longitudinal axis and extending from a cold side of the combustor panel, the attachment feature comprising a tip portion and a base portion, wherein the attachment feature is configured to extend through the combustor shell such that the tip portion is disposed outward of a diffuser-facing side of the combustor shell, wherein the base portion is configured to be disposed between the cold side of the combustor panel and the diffuser-facing side of the combustor shell; wherein the combustor panel is coupled to the combustor shell via the attachment feature, the attachment feature extending through a hole in the combustor shell, wherein an annular cooling cavity is defined between the combustor shell and the combustor panel; and wherein the attachment feature defines a core passage extending from an inlet opening for receiving cooling air from a diffuser chamber that is at least partially defined by the diffuser-facing side of the combustor shell, the inlet opening defined on the tip portion and extending partially through the attachment feature to terminate within the attachment feature, and an offshoot passage extending from the core passage to an outlet opening for delivering the cooling air to the annular cooling cavity adjacent the attachment feature, the outlet opening defined on the base portion, the core passage and the offshoot passage collectively forming a cooling airflow conduit which extends through the attachment feature; characterised in that: the outlet opening of the offshoot passage is at least partially disposed within the hole in the combustor shell.