Physical attractiveness plays a very important role in determining communication effectiveness and attitude change. Physical attractiveness elicits positive emotional responses during initial contacts. Attractive people are typically rated as more desirable, socially acceptable, respectable, and influential that their less attractive counterparts.
Some suggest that physically attractive celebrity endorsers elicit better brand recall than unattractive celebrity endorsers. Commercials and advertisements confirm the effectiveness of using attractive celebrity spokespersons, as they create a more positive attitude towards ads featuring an "attractive" product. Companies use celebrities because they are familiar to the public.
Sometimes being too good-looking can backfire. The audience may not be impressed by their appearance and view the person as not credible. But if the audience is not overly concerned about expertise, then attractiveness is more desirable.