If you are a celebrity looking for a personal trainer then I feel the following five points are important to get right:
You want to make sure that your personal trainer holds the highest level qualifications. In addition to basic entry level qualifications look for Paul Chek or Poliquin qualifications as they represent some of the best in the industry.
Experience counts for a lot as someone who is newly qualified is unlikely to possess highly refined skills. Look for a trainer with at least 5 years of experience.
Make sure the trainer has the capacity to take you on as a client and can train you at the times you are going to be free. If you have an erratic schedule, you might want to look for a trainer that can provide workouts on video, or Skype sessions. Look at your schedule and have a think about what level of service you are going to have to look for.
Trust is a big issue for celebrities when they are training with their trainers. You would definitely need a disclosure agreement to protect yourself against your trainer passing on sensitive information about your training regime, personal information, or schedule. Look to employ a personal trainer with a lot of integrity, someone you can feel comfortable training with.
Good Personality Fit
Finally, having a good personality fit with your trainer is very important so you can get the most out of your training regime.