Appeal to celebrity
| Cogito ergo sum|
Logic and rhetoric
An appeal to celebrity is a fallacy that occurs when a source is claimed to be authoritative because of their popularity. It is the bastard child of an appeal to authority and an argumentum ad populum. The appeal to celebrity is especially common in advertising.
- P1: Famous person X supports Y.
- P2: (unstated) Famous persons are correct.
- C: Y is correct.
- A large part of the appeal of fascism and other right-wing populist movements relies on the idea of the “will of the people” usually centered around a charismatic figure In other words, the celebrity style politician/dictator must be right — they draw huge crowds, so therefore they represent the ‘will of the people’. To reduce it to the absolute level of absurdity — Hitler had 66 million fans; who am I to disagree?
- Donald Trump's use of the reality TV show The Apprentice to help win the presidency. Many people voted for Trump because they thought he was an astute businessman who would improve the U.S. economy.
- Jenny McCarthy’s use of celebrity to spread pseudoscientific ideas 
- Gwyneth Paltrow using her celebrity to sell ridiculous ideas such as vaginal steaming 
- John McAfee using his notoriety as a cybersecurity "expert" to shill cryptocurrency. 
- The Wall Street Journal using actress and health industry non-expert Suzanne Somers to comment about the Affordable Care Act. 
It is well known in academic business studies that celebrity endorsements significantly increase advertising effectiveness.  Therefore the most common form of appeal to celebrity, the usage of celebrities to endorse products in advertisements, happens far too often to note individual instances. Celebrity endorsements of products should be considered only at face value: they are when a company pays a celebrity, as part of marketing branding, to boost brand awareness by increasing buzz around a product with a positive review.  Nothing more, nothing less. The celebrity in question may or may not like the product, they get paid either way. It is not uncommon for a celebrity to endorse one product, and then be spotted in public with a competitor's product.  Even if they are contractually obligated to use the endorsed product in public. 
It is also worth noting that scammers will frequently depict celebrities, almost always without authorization, "endorsing" the scam in their own promotions. This is particularly common for get-rich-quick / investment type scams,  scams promoting bullshit health products like supplements,  and celebrity imposter scams, where a scammer impersonates a celebrity to fleece a victim into donating money towards a fake charity or other similar ruse.  Even Mehmet Oz (not exactly one without questionable product endorsements) has to fight back against people falsely using Oz's name to push out their own bullshit health products. 
Popularity is irrelevant to truth. The only minor exception occurs when the cited celebrity is popular because of their expertise (e.g., Richard Dawkins, Stephen Hawking, and Neil deGrasse Tyson in their respective fields), which merely shows (in this case) that said persons are good at explaining science, not necessarily doing it. It also doesn't follow that, for instance, Dawkins's expertise in biology gives him any particular authority in questions of religion, or for that matter other branches of science such as physics or astronomy. Similarly, Michael Jordan may be an authority on basketball shoes, but because of his expertise at basketball, not because of his popularity. This also works for Canadian pop singers Tegan and Sara talking about LGBTQ issues (via their charity) because they are gay.
- "Celebrity Endorsement", Bruce Thompson
- "Appeal to Celebrity", Fallacy Files
- "APPEAL TO CELEBRITY", Logically Fallacious
- "Appeal to Celebrity", the Skeptic's Field Guide
- "What Is Appeal to Celebrity? Definition and Examples"
- Eco, U., 1995. Ur-Fascism
- "The TV that Created Donald Trump" by Emily Nussbaum, New Yorker, 2017 July 24
- "Donald Trump won election because 'Apprentice' viewers believed in his TV character: study" by Douglas Perry, Oregonian, 2018 March 12
- "Jenny McCarthy's "Mission" to Spread Pseudo-Science.", Mconvente, Daily Kos, 2009 August 15
- "Gwyneth Paltrow advises women to 'steam-clean' their vaginas." by Megan Blandford, Sydney Morning Herald, 2015 January 30
- "John McAfee reveals he charges $105,000 per promotional cryptocurrency tweet" by Shannon Liao, Verge, 2018 April 2
- "A Celebrity Journal fiasco: Quack-loving Suzanne Somers, WSJ "expert" on health care" by Ryan Chittum, Columbia Journalism Review, 2013 October 29
- Alexander P. Schouten, Loes Janssen & Maegan Verspaget (2020) Celebrity vs. Influencer endorsements in advertising: the role of identification, credibility, and Product-Endorser fit, International Journal of Advertising, 39:2, 258-281, DOI: 10.1080/02650487.2019.1634898
- "The Effect of Celebrities in Advertisements" by Hashaw, Houston Chronicle, 2019 March 29
- "8 Celebrities Who Are Very Bad At Endorsing Products" by Brendan Klinkenberg, Buzzfeed News, 2015 July 15
- "Charlize Theron: A tale of two watches" by Oliver Marre, Guardian, 2008 October 14
- "Why You Should Avoid Celebrity Endorsement Scams Like the Plague" by Donna Fuscaldo, Motley Fool, 2019 November 14
- "Celebrity scam alert as criminals use rich and famous to lure online victims", National Cyber Security Centre bulletin, 2020 August 14
- "Spotting Fake Celebrity Endorsements Of Diet And Health Remedies" by Bruce Y. Lee, Forbes, 2016 October 3
- "Celebrity Impostor Scams", AARP resource center
- "Dr. Oz leads charge against false celebrity endorsements", Gainesville Sun, 2019 April 30