Through the questions your hypnotist will ask, you will begin to experiencing a story. This story is a past life. Usually you have been guided to the story because it has something to do with this lifetime. If you look into the eyes of the people in your story, you will be able to determine if you know them in this lifetime. Many lessons we carry from lifetime to lifetime, because we don't learn them.
Many fears also come from another lifetime.
By leaving them in the past-life, we can eliminate them in this lifetime. Although it is possible that you were someone famous, it is more likely that you were just a person learning lessons and experiencing life. You will retain all the information you learned in your story. Being hypnotized is much like going into a meditative state. You are fully aware and you will not do anything under hypnosis that you normally wouldn't do.