Following a mixed-method approach, this study extends the literature on high-tech-high-touch services by examining the effect of supplementary human service in robot-prominent service encounters. Findings across two empirical studies demonstrate that, in such service encounters, offering supplementary human service can enhance consumers’ perceived social value of the experience and boost their attitudes and repurchase intentions towards the service business. However, this effect only applies when the robot is programmed to take on interactive (vs. non-interactive) service tasks; a lack of perceived social value is more salient in the former (vs. latter) scenario. Perceived social value is the underlying psychological mechanism driving the above effects. This research further reveals service encounter type as the boundary factor conditioning the interaction effect of focal service task and supplementary human services. Results provide valuable theoretical contributions and managerial implications for hospitality management.