The concept of co-creation with consumers has been extensively studied in the literature documented in innovation management and marketing literatures. In this study, we contribute to the literature threefold. First, we develop a model to investigate how co-creation with fans enhance purchase intent and engagement of other customers. Second, we test the model using the data collected from consumers on four different product categories including beer, car, cosmetics and travel. By doing so, we examine the differences between product vs. service as well as different product categories. Third, we will compare the results with that of ordinary consumers to check if there are any differences in the case of co-creating with fans. Most of the extant studies have found a positive effect of co-creation on the outcome evaluation. However, engaging other consumers by co-creation with fans has not been studied. For bridging this research gap, we developed a conceptual model to investigate the antecedents and consequences of co-creation with fans. The hypotheses are as follows. H1: Product class involvement and domain specific knowledge affect perception on co-creation positively. H2: Perception on co-creation affects purchase intent and word-of-mouth positively. H3: The relationships of H1 and H2 differs depending on product categories. H4: The relationships of H1 and H2 differs if companies work with ordinary customers or fans. We tested the hypotheses with the data collected from consumers an online questionnaire survey. Data collection was conducted through a market research agency in 2016 for beer and cars, and in 2019 for cosmetics and travel. The data was collected from 240 consumers in their 20s, 30s, and 40s in Japan. Each segment has same number of males and females, 40 people each for six segments. The findings shed a new light on the co-creation literature and help companies to design better co-creation with fans in different product and service categories.