This paper aims to sketch a comparison of the different and sometimes complementary approaches of Lacan and Dolto to the theory of becoming a subject - through bringing to light Dolto's clinical contributions to the Mirror Stage - and the development of her own theory on the Unconscious Image of the Body. This paper makes extensive use of the correspondence between Dolto and Lacan published in 2005, as well as of the references they made to each other in their written work. Both have a Freudian theoretical background, but Dolto's theories are built upwards from the observation of infant and child development as well as from their treatment, whilst Lacan's stems from adult psychoanalysis, the re-reading of Freud's cases and structural anthropology and linguistics. Through this paper I hope to bring to the Anglo-Saxon attention the fascinating seminal interaction of this famous French ‘parental couple’.