PurposeThis study aims to exploit the match‐up effect to fashion collaborations by distinguishing the consumers' fit association at a cognitive and attitudinal level. It seeks to investigate the mediating role of the match‐up perception by identifying the antecedents of match‐up perception and the attitude formation in co‐marketing alliance.Design/methodology/approachA total of 273 Korean women were surveyed to compare the product/brand associations, and assess the level of match‐up perception and overall attitude toward the two fictitious co‐marketing alliance cases.FindingsThe study argued that the match‐up perception mediated between framing criteria and the attitude toward co‐marketing alliance. Usage situation, user identity, and perceived brand equity were valuable factors in the perception of alliance match‐up. This match‐up perception at a cognition level is a necessary condition prior to consumer attitude at an attitudinal level.Research limitations/implicationsThe research stimuli are limited to two fictitious alliance cases. Expanding cases to diverse product categories and brands' stimuli enhances the empirical validity. The cross‐cultural approach with diverse regions is further considered for enhancing research reliability.Originality/valueThe study exhibits an innovative fashion collaboration phenomenon. On empirically demonstrating the mediating effect of match‐up perception in the context of co‐marketing alliance, the study suggests the theoretical and practical insights in the Korean and global fashion industries.