Informal invitation letter to a social event should be short and to the point. It should always convey enthusiasm and be thankful for the invitation. Clear all the necessary doubts of the event and confirm the date, time venue of the event to avoid confusions. Let the person know that you are excited about the event.
Thank you very much for inviting me for the dance program. I have heard a lot about your dance but could not attend any of the programs. I have always heard that you dance extremely well and I am happy that you are getting chance to dance on a stage where the bigwigs of the entertainment t industry would be coming. My brother always says that you dance so well that t you will definitely become a choreographer.
I am so glad that you called me for this event as it is very difficult to get tickets for the event .I will make sure that I am free that day and come and enjoy your dance program and pray that you get all success you want from this dance event. I would be there on time on ____________(day) at ________(venue) by _______(time).