This paper explores a partnership between British American Tobacco (BAT) and the environmental organisation Earthwatch Europe (EE) and considers its implications for countries implementing Article 5.3 of the World Health Organization Framework Convention on Tobacco Control. We reviewed approximately 100 internal BAT documents, interviewed EE's former executive director and examined media accounts and BAT and EE websites. We analysed materials by reviewing them iteratively, identifying themes, constructing a timeline of events and assembling a case study. BAT sought a partnership with EE to gain a global ally that could provide entrée into the larger non-governmental organisation (NGO) community. EE debated the ethics of working with BAT, resolving them in BAT's favour and taking a narrow view of its own overall organisational mission. To protect its reputation, EE delayed public disclosure of the partnership. Instead, EE promoted it to policy-makers and other NGOs, extending BAT's reputation and reach into influential circles. The potential for normalising the tobacco industry presence within government through NGO partnerships and the benefits that accrued to BAT even when the partnership was not being publicised show why governments seeking to protect effective tobacco control policies from industry influence need to consider ways to identify and discourage 'hidden' NGO partnerships.