Alongside the COVID-19 pandemic, the World Health Organisation has recognised an ‘infodemic’ of mis- and disinformation (UN, 2020), generating doubt and fear about the causes, spread, and remedies of coronavirus. Using the example of a prominent conspiracy theory relating to the COVID-19 pandemic, this presentation uses large-scale datasets to investigate the spread of such content through social and mainstream media, paying particular attention especially to the processes by which conspiracy theories move from small-scale conspiracist communities to wider social media circulation, and from there to mainstream media coverage and substantial societal impact. In doing so, it highlights the role of celebrities and entertainment media as potential conduits for conspiracist material from fringe spaces to much greater circulation, and point to a pronounced lack of critical coverage and societally responsible journalistic gatekeeping in such ‘soft news’ coverage. Building on this analysis, I formulate a number of key recommendations to political, media, and industry stakeholders seeking to combat the spread of mis- and disinformation.