Just so you're aware, not everyone has the capability to add performers to an event. Our system is setup right now so that only a person that controls a performer profile can add that performer to an event. If you do not control the performer profile that you're trying to add to an event, I recommend you make note of the performer in the title and description of the event. You can let us know and we can help add the performer to your listing.
Eventful has millions of performer profiles, but we don't have everything. If you are trying to add a performer that we do not have listed on our site, you will need to create a performer profile for them. Let us know if you need help.