Singlish is a contact variety spoken in Singapore that is characterised by the optionality of agreement morphology. In particular, the -s verbal agreement morpheme with third-person singular subjects in present tense clauses has been argued to be in morphophonological free variation with a null allomorph (Wee and Ansaldo 2004). The paper presents a number of new empirical observations to demonstrate that the lack of agreement morphology (termed agreement-drop) corresponds to a difference in the structural configuration of the left periphery. In particular, the paper extends Bao's (2015) and Sato's (2016) treatments of Singlish as being a topic-prominent language by arguing that the ostensible subjects in agreement-drop constructions are underlyingly topics, which are base-generated in a structurally higher position; the canonical subject position is instead filled by a pro which is coindexed with the higher topic, extending Bao's (2015) analysis for other topicalisation structures in Singlish.