This paper aims at investigating the linguistic devices used to carry out the persuasive functions of metadiscourse markers employed in David Beckham and Millie Bobby Brown's speeches at UNICEF, New York, November 20, 2019. It also aims at identifying the similarities and the differences between the various persuasive appeals and strategies employed in the speeches of those two celebrities. In order to carry out these goals, the research follows Conner and Lauer's (1985) model of persuasion and Dafouz-Milne's (2008) theory of metadiscourse markers. Results suggest that many subcategories of both textual and interpersonal metadiscourse markers are found in the speeches of both goodwill ambassadors except for reminders, topicalisers and probability adverbs, but there are some variations in using them. Findings also prove that logical markers are the most used textual metadiscourse markers in both discourses and that the dominant interpersonal linguistic features in both speeches are those which belong to the category of commentaries. According to the use of different persuasive appeals, rational appeal is mostly used by Beckham and Millie.