My Dear (name),
I have just received your letter and find the mission for which the music and dance concert is being arranged as laudatory. It is a humanitarian job. I have given a thought to the project and hereby accept your invitation.
I’ll be flying to __________________ on the 1__________ instant and reaching the airport at ____________________. My performance will be gratis and without any charge. I’ll be glad to contribute my might towards fulfillment of the very laudable object for which it is meant.