For starters you don’t want just any voice. A celeb voice should be very memorable and recognizable. Your signature voice should sound like nothing else in the market or industry. So when choosing a celebrity voice, clearly define this need and any characteristics you might like the voice to have. Ask yourself what your company sounds like and include that description in the audition.
Lots of companies are employing celebs to give instant recognition to their brand. Sarah Jessica Parker - Barnes and Noble, Morgan Freeman - Visa, and Keifer Sutherland - Bank of America are perfect examples of recognizable celeb voices.
Next, be prepared to make a financial and time commitment. The use of a celeb voice should come with a well thought out plan of longevity. Take your time and don’t rush the selection process. Also make sure that the talent being considered are aware of the commitment and when you will need to record. Make sure they do not have scheduling issues, films, etc that would render them unavailable for large lengths of time or make recording difficult.
Celebrity Voices can be expensive, so make sure you have the budget in place before you make your final decision. Voices that are very unique and recognizable will typically cost more and you may need to consider having the talent enter into an exclusivity contract that would restrict them from taking work of a similar nature in your market, sector or industry. You’ll need to check with your casting company to make sure there are no exclusions in place for your celeb.