Artificial intelligence (AI) is reshaping journalism at an unprecedented pace, challenging long-held assumptions about what makes news credible, authentic, and human. As AI systems increasingly generate, curate, and personalize information, societies around the world are grappling with questions about how this transformation affects trust in the media and the perceived integrity of journalism. Scholars have highlighted that AI not only changes newsroom practices but also redefines audiences' expectations of journalistic values such as accuracy and transparency. Yet, public perceptions of these changes remain under-explored from a global, comparative perspective, as previous research has mainly taken a Western perspective. This study, therefore, examines to what extent individuals' attitudes toward AI in journalism and perceptions of authenticity differ across six culturally diverse countries: Brazil, Denmark, Japan, the Netherlands, South Africa, and the United States. Using nationally representative surveys (N = 6,961), we analyze four core dimensions: (1) journalistic principles for AI-supported news, (2) individual engagement intentions for AI-supported news, (3) general authenticity perceptions across different dimensions and (4) the perceived impact of AI on them. Our findings show significant cross-national heterogeneity in attitudes toward AI in journalism, with more pronounced optimism in South Africa and Brazil and more pronounced skepticism in Western countries. Moreover, we frequently find ambivalent attitudes, as well as high degrees of heterogeneity within individual countries as well, with self-reported generative AI use emerging as one explanatory factor. Engagement intentions demonstrate a trend for ignoring AI-supported news, particularly in Western contexts, alongside a universal reluctance to share such content. This reflects broader trust issues and reputational concerns. Despite these differences, respondents across all countries converge on the importance of the human element when it comes to authenticity, rooted in journalists' character and values.