While self-efficacy appears as a main behaviour’s explanatory variable, little research has been conducted regarding the potential mechanisms that could improve self-efficacy in the specific context of marketing communication. Moreover, despite the strong stakes linked with organ and gamete donations, such causes have received little attention from researchers in social marketing and persuasive communication. Through research, vicarious experience (observation learning) appeared as one of the main levers of self-efficacy. The objective was to transpose this vicarious experience in an imaginary context by activating transportation mental imagery. This transportation experience, provoked by narrative communications and involving receiver’s identification to the main character of the story, leads to receiver’s desire to look like the donor and to the reinforcement of their self-efficacy to donate their organs / gametes. Two independent studies were conducted in order to test and validate the proposed research model. Contributions and limits of this research are highlighted and potential future research directions are presented.