Instagram has become a growing platform for users to share media reflecting their interests like food, travel, fashion etc. In addition, it is heavily used by marketers and influencers to reach out to potential audience by advertising their content. The number of likes received on posts reflects social reputation of the users, and in some cases, social media influencers with a large reach are also compensated by marketers to promote products. This has led to users artificially bolstering the likes they receive to project an inflated social worth. Our analysis on over 20,000 likes spanning 18,091 posts from 1000 users, reveals that fake engagement on Instagram has distinct features. In this study, we build an automated mechanism to detect fake likes on Instagram, and estimate the true reach of a user. We achieve a high precision of 92% to detect fake likes. We further validate the efficiency of our model to perform an in-the-wild study and label 1,34,021 like instances, identifying 8,845 previously unknown fake likes.