A method of assembling an annular combustion chamber assembly, the annular combustion chamber comprising an annular upstream end wall, a radially outer annular wall, a radially inner annular wall, a first ring and a second ring, the first ring having a greater diameter than the second ring, the radially outer annular wall comprising a plurality of first combustion chamber segments and the radially inner annular wall comprising a plurality of second combustion chamber segments, characterised in that each first combustion chamber segment comprises a rigid frame, the frame comprises first and second end walls (76, 78) and first and second edge walls (80, 82), the rigid frame has a first hook at a first circumferential end of the first combustion chamber segment and a second hook at a second circumferential end of the first combustion chamber segment, the first hook is provided on the first edge wall and the second hook is provided on the second edge wall,_the first hook extends circumferentially away from the first combustion chamber segment, the second hook forms a slot with the frame, each second combustion chamber segment comprises a rigid frame, the frame comprises first and second end walls (76, 78) and first and second edge walls (80, 82), the rigid frame has a first hook at a first circumferential end of the second combustion chamber segment and a second hook at a second circumferential end of the second combustion chamber segment, the first hook is provided on the first edge wall and the second hook is provided on the second edge wall, the first hook extends circumferentially away from the second combustion chamber segment, the second hook forms a slot with the frame, the combustion chamber segments (58, 60) comprising an integral frame and an inner wall, the method comprising the steps of: a) positioning the first combustion chamber segments circumferentially side by side to form an annulus comprising positioning the first hook of each first combustion chamber segment into the slot of a circumferentially adjacent first combustion chamber segment and removably securing the downstream end of each first combustion chamber segment to the first ring to form a first assembly, b) positioning the second combustion chamber segments circumferentially side by side to form an annulus comprising positioning the first hook of each second combustion chamber segment into the slot of a circumferentially adjacent second combustion chamber segment, removably securing the downstream end of each second combustion chamber segment to the second ring to form a second assembly, c) locating the second assembly within the first assembly, d) removably securing the upstream end of each second combustion chamber segment of the second assembly to the annular upstream end wall, and e) removably securing the upstream end of each first combustion chamber segment of the first assembly to the annular upstream end wall. a) positioning the first combustion chamber segments circumferentially side by side to form an annulus comprising positioning the first hook of each first combustion chamber segment into the slot of a circumferentially adjacent first combustion chamber segment and removably securing the downstream end of each first combustion chamber segment to the first ring to form a first assembly, b) positioning the second combustion chamber segments circumferentially side by side to form an annulus comprising positioning the first hook of each second combustion chamber segment into the slot of a circumferentially adjacent second combustion chamber segment, removably securing the downstream end of each second combustion chamber segment to the second ring to form a second assembly, c) locating the second assembly within the first assembly, d) removably securing the upstream end of each second combustion chamber segment of the second assembly to the annular upstream end wall, and e) removably securing the upstream end of each first combustion chamber segment of the first assembly to the annular upstream end wall.