Definition of infringement of portrait rights: without the consent of others, using other people's photos and other portraits for commercial propaganda belongs to infringement of other people's portrait rights. Except for public welfare propaganda.
The crux of your problem lies in what you do with that photo. If it's just an exhibition, that's fine, but if it's used in commercial advertisements, it will infringe on the portrait rights of others. In the photos you use to promote, people will easily notice the star instead of you, so you are still using other people's portraits to promote, which is the essence of the event.