The impact of celebrities on public awareness in health communication has been proved to be significant, making it a possible approach for risk communication during public health emergencies. In the early stages of COVID-19, some Chinese medical experts engaged with the public and became "celebrity scientists." It provides representative cases for studying celebrity-based risk communication approaches. With Dr. Wenhong Zhang as the primary case, this research investigates the construction process of celebrity scientists. Through semantic network analysis (SemNA) and other complementary methods, this study examines Dr. Zhang's articles (n1 = 45), relevant news reports (n2 = 360), and public tweets (n3 = 12,933), in order to identify the main agendas of media, public and expert during the construction process of celebrity scientists, as well as their similarities and differences. The results reveal three categories in the narratives around the celebrity scientist, highlighting unbalanced focuses and preferences. Notably, the agendas of celebrity scientists, media outlets and the general public are more alike than different, and tend to converge over time. The simultaneous resonance of the media and public is also crucial in the construction of celebrity scientists, as well as specific incidents or turning points. These findings shed light on the application of celebrity-based risk communication approach in emergencies, providing guidance and discussion points for health messaging strategies as well.