Breathing instruction for classical singing is becoming more physiologically focused, yet the effect of chest-wall kinematic directives on breathing behaviour is largely unexplored. Five female classical singers sang Caccini's Ave Maria without directive and under two directives: 'steadily pull the abdomen inward' and 'steadily expand the abdomen' through each phrase. The directives had a statistically significant effect on chest-wall dimension at initiation of phrase and on excursion, but dimension at termination of each phrase reverted to habitual behaviour. Rib-cage dimensional change counteracted abdominal change so that lung volume measures were consistent within singer across all breathing conditions. The results have implications for the distinction between consciously controlled and innate respiratory behaviours in singing. Implications for singing pedagogy are discussed.