Vicarious interaction on live streams can occur when viewers experience what it is like to interact with a live stream persona by observing other viewers’ interactions with the persona. This study examined how vicarious interaction can cultivate parasocial relationships (PSRs) with live stream performers. Mechanical Turk workers were randomly assigned to view a clip of a live stream that either contained or did not contain instances in which the host addressed specific viewers in her audience. Results revealed an indirect effect of host–viewer interactions on PSR strength through participants’ imagination of how responsive the host seemed to other viewers. This effect was enhanced by parasocial interaction with the host. This study provides evidence of a secondhand, vicarious pathway to the development of PSRs.