New Twist on a Christmas Carol

My just 5 year old granddaughter came home delighted with the carol she and her class are learning at reception. Unfortunately she misunderstood the words. "Mary and Jessica's baby Jesus is born..." she sang. We burst into laughter and told her it should be Mary and Joseph. She  burst into tears and said it really is Mary and Jessica. I hope her voice singing Jessica won't come across loud and clear at the carol service.