In previous research on advertising discourse, not much attention was given to the significance of the linguistic choices used by endorsers to show their power of identity. This study aims to analyze the linguistic choices made in three ads of Children Cancer Hospital Egypt 57357 (57357 CCHE) to show the power of identity of political and social authority. Only the parts in which the authorities give their unfiltered verbal feedback on their visit to 57357 CCHE are chosen to be investigated. The uniqueness of the event in which a social authority appears as a political authority (conscript) in 57357 CCHE advertisements urged the need to explore the discourse of such ads to consider the power of identity. The first advertisement is that of the political authority (Egyptian Armed Forces representative) visit to 57357 CCHE. The second advertisement is that in which Egyptian celebrity Mohamed Ramadan as a conscript (a political authority) gives his verbal feedback on the visit to 57357 CCHE. In the third ad, Mohamed Ramadan as a social authority visits 57357 CCHE. A Critical Discourse analysis is applied through Holliday’s Systemic Functional linguistic (SFL) approach. Based on the ideational, interpersonal and textual analysis, it is concluded that each of the authorities derives his power of identity from the authority he embodies. The power of identity affected the linguistic choices, the logical sequence of discourse and the use of language by the endorsers to relate to audience.