Recent theorizing on the nature and function of gratitude (the find-remind-and-bind theory; Algoe, 2012) stipulates that expressing gratitude should serve to alert previously unacquainted peers to the potential for a high-quality social bond (i.e., a find function). Although the logic of this premise is supported by extant research, it has not, as yet, been tested empirically. In the current study, participants received a note from a previously unacquainted peer that contained an expression of gratitude (or did not) with regard to prior benefits provided by the participant. After providing ratings of the peer and ostensibly completing the study, participants were given an opportunity to spontaneously give their contact information to the peer, which served as a behavioral measure of affiliation. In line with the proposed find function of gratitude expressions, recipients of expressions of gratitude were more likely to extend the effort to continue the relationship with the novel peer by providing that peer with a means to contact them. This experiment also provided evidence that perceptions of interpersonal warmth (e.g., friendliness, thoughtfulness) serve as the mechanism via which gratitude expressions facilitate affiliation: insofar as gratitude expressions signaled interpersonal warmth of the expresser, they prompted investment in the burgeoning social bond. As such, these findings provide the first empirical evidence regarding 1 of the 3 central premises of the find-remind-and-bind theory of gratitude (Algoe, 2012) in the context of novel relationships.