The use of generative artificial intelligence (GAI) for advertising is raising issues around ethics and transparency. This type of AI adds an extra manipulative layer to advertisements because it makes it harder for consumers to determine whether elements of an ad are real or AI-generated. This study aims to explore the effect of AI disclosures in GAI-created advertisements on trust in the advertisement and the organization. Moreover, this study tests whether these effects can be explained by conceptual AI knowledge and attitudinal persuasion knowledge. A one-factorial (GAI advertisement with versus without disclosure) between-subjects design experiment was conducted (N = 304). The results showed that AI disclosures increased conceptual AI knowledge and attitudinal persuasion knowledge, resulting in a decrease in trust towards the advertisement and organization. However, a positive effect of AI disclosures was also found, whereby the disclosure increased attitudinal persuasion knowledge, which lead to an increase in trust.