Spokesperson
A "spokesman", "spokeswoman" or "spokesperson" is someone engaged or elected to speak on behalf of others.
Duties and function
In the present media-sensitive world, many organizations are increasingly likely to employ professionals who have received formal training in journalism, communications, public relations and public affairs in this role in order to ensure that public announcements are made in the most appropriate fashion and through the most appropriate channels to maximize the impact of favorable messages, and to minimize the impact of unfavorable messages. Celebrity spokesmen such as popular local and national sports stars (such as Michael Jordan or Bob Uecker) are often chosen as spokesmen for commercial advertising.
Responsibilities
Unlike an individual giving a personal testimonial, it is the job of a spokesman to faithfully represent and advocate for the organization's positions, even when these conflict with his own opinion. Many celebrities have done work as spokesman. As a result, spokesmen are generally selected from experienced, long-time employees or other people who are known to support the organization's goals.