As generative AI (GenAI) policies in higher education in Thailand have been introduced, inquiries regarding GenAI integration and adoption in teaching and learning have been raised. Delving into a relatively unexplored interdisciplinary area in this context, this study aimed to investigate students' responses towards the use of GenAI in academic and professional public relations (PR) writing, employing the Diffusion of Innovations (DOI) and the Technology Acceptance Model (TAM) frameworks. This qualitative study was conducted using semi-structured focus group sessions among native Thai PR major university students, with a workshop on GenAI prior to the discussion on its adoption. The findings revealed that all participants were aware of GenAI and most had utilized it for daily and academic purposes, but never in professional PR writing. Despite having positive attitudes towards its use after the trial, they recognized certain drawbacks and concerns and expressed some reservations towards adopting GenAI in their future academic and professional PR writing, rather in English than in Thai. Besides knowledge and perceptions, individual characteristics were also attributed to hindering GenAI adoption among some participants. Therefore, providing adequate resources and practical guidelines on appropriate GenAI use are crucial. Future research in other subject areas and languages is suggested.