This research aims to determine the role of brand ambassador strength consisting of attractiveness, trustworthiness and expertise on purchase decision mediated by attitude towards the brand Scarlett Whitening. As business competition in the market increases, marketers must develop new things and optimize marketing strategies to compete effectively, one of which is using brand ambassadors. The role of brand ambassadors as a credible source in introducing brands to consumers can increase consumer purchasing decisions. The object of this research is the Scarlett Whitening beauty product which uses Song Joong Ki as its brand ambassador. This research is aimed at consumers of Scarlett Whitening beauty products that lives in the Jabodetabek area who follows Song Joong Ki's social media on Instagram or Tiktok. This research uses quantitative research methods and uses online survey questionnaires to collect data from the target population. Around 230 respondents were gathered for the actual test. Data were analyzed using SPSS 25 and AMOS 22, and tests included validity and reliability, model suitability, and hypothesis testing. The research results show that attractiveness and trustworthiness have an impact on brand attitude, brand attitude has an impact on purchase decisions and attractiveness and trustworthiness have an impact on purchase decisions. Apart from that, it was found that there was no impact of expertise on brand attitude and purchase decisions. Moreover, this research has contributed to past research on improving consumer purchasing decisions.