The Securities and Exchange Commission of the United States (SEC) stated that advertising ICO and other types of investment by celebrities may be illegal. The statement is published on the regulator's website.
Celebrities who receive rewards for advertising ICO and do not disclose the amount of fees violate the law. Recommendations from celebrities can not be a guarantee of the legitimacy of the ICO.
The regulator warned investors that the intention to invest should not depend on the opinions of actors, athletes and other stars. The SEC recommended that investors check the independence of sources and distinguish advertising from recommendations.
October 27, 2017 edition of the NYT spoke about the celebrities involved in advertising ICO of various projects. These included rapper DJ Khaled, boxer Floyd Mayweather and Paris Hilton. You can read more here:
https://www.nytimes.com/2017/10/27/technology/how-floyd-mayweather-helped-two-young-guys-from-miami-get-rich.html