I suggest that you wear something nice; however, there should be no jeans or sneakers...just out of respect for the mistress who is performing on stage. When I attended Ms. McKennitt's most recent performance, I was wearing a blouse, a skirt, some tights and a dress jacket. Although it was, to some extent, dressy, it was kind of simple. Remember, look presentable. You may never know if you will meet Loreena McKennitt herself. It's like going to a formal dinner with a duchess or maybe even a princess. On top of that, you are going to see a woman who was just made Honorary Colonel of the entire Royal Canadian Air Force. That, of course, is important.