A diffusion bonded and superplastically formed turbomachine blade, the turbomachine blade comprising: a first layer (4); a second layer (6); and a membrane (2) disposed between the first and second layers (4, 6); wherein the membrane (2) is diffusion bonded to the first layer (4) along a plurality of first strips (10) and the membrane (2) is diffusion bonded to the second layer (6) along a plurality of second strips (12), wherein the first and second strips (10, 12) are offset from one another so that the membrane (2) is bonded to the first and second layers (4, 6) in an alternating pattern; wherein the membrane (2) has a recess (28) which extends into an area between an adjacent pair of first or second strips (10, 12).