This article examines the online circulation of the slogan ‘Je suis Charlie’ which went viral on social media after the Charlie Hebdo attacks in Paris in January 2015. Building first on recent literature on digital virality, it approaches the slogan’s circulation in terms of the transfer of affective intensities among network connections and with consideration to the function of social media algorithms in bringing about network encounters. Two samples of tweets using the slogan are analysed to highlight the emergence of subjective relations to Charlie from within networked circuits of affect. The declaration ‘Je suis Charlie’ is argued to be a performance of affective citizenship in the name of social cohesion while also constructing ‘affect aliens’.