Partnering with social media influencers on Instagram has proven successful in reaching consumers where they are. As influencer marketing progresses, it is important to understand what drive audience to engage with influencer contents. Engagement, as an outcome of influencer content, has been understudied in marketing literature, with researchers yet to explore the extent to which it impacts attitude. This work studies the antecedents to engagement with influencer's publications focusing on two underexplored dimensions, the perceived interest of the publication and the perception of its advertising nature. The results of the experiment implemented indicate that the perceived interest of an SMI’s content significantly reinforces engagement with sponsored contents, especially among individuals who are open to brands being present in SMI content and when the transparency of this content is perceived as high. Managerial and theoretical implications are then discussed.