A combustor wall element arrangement for a gas turbine engine comprises an upstream wall element (50A) overlapping a downstream wall element (50B) and defining a gap (37) and an outlet (35) therebetween. In use, a coolant flow exits the outlet (35) to provide a coolant film (D) across at least a part of the downstream wall element (50B). The outlet (35) has a smaller dimension, normal to the downstream wall element (50B), than the gap (37) thereby increasing the velocity of the coolant flow across at the downstream wall element (50B). The resultant film coolant flow is effective further across the downstream wall element.