During the outbreak of an epidemic, the success in risk communications to make the public comply with disease preventive measures depends on the public's trust in the government. In this study, we aim to understand how media audiences update their trust in the government during the COVID-19 outbreak depending on the information they received. We conducted an online survey experiment in February 2020 in Hong Kong (n = 1,016) in which respondents were randomly provided with a government press release and an endorsement either from an official or a non-official source. This study shows that the information from a non-official source enhances the credibility of official government messages. Our findings imply that dictators can actually "borrow credibility" from their citizen journalists and even nondemocratic leaders can make themselves more trustworthy to potential dissenters through citizen journalism. Allowing information flow from non-official sources can be a practical measure for governments to address the problem of a credibility deficit during a pandemic.