The Big Question: an etiquette guide to ballet and opera for beginners Don't worry about what to wear. There are people in black tie but except at Glyndebourne, of course, when you have to wear black tie and formal dress and some galas where a dress code will be specified, you can wear pretty much what you want. Dress as if you were going to the theatre and don't fret. The audience listens to the overture in reverential silence. But when there's a show-stopping aria don't be surprised if they burst into appreciative applause and shouts. The same goes for ballet. If someone does something on stage that makes your heart stop, then they are likely to be applauded. Russian dancers, in particular, expect to be applauded a lot. If you are tempted to join in the chorus of praise remember that opera and ballet lovers like getting their Italian gender endings correct. So: "brava!" for a woman, "bravo!" for man and "bravi!" for everyone. On the other hand, you can just whistle, shout or stay entirely silent depending on your mood. Listen out for boos. Unlike in straight theatre, opera and more rarely ballet audiences are unafraid of expressing their views. Often this is aimed at a particular performer, the conductor or - if it's an especially radical production - the director. This is particularly pronounced in Italy, where boos regularly greet the end of a production. Less so here, but not unknown. Don't feel anxious about the price of food and drink in the bars. While you may wish to make a night out of it, it is quite all right to go to the opera or ballet having eaten in advance (indeed if the performance is long it is positively advisable) and then to drink the free tap water. Equally though programmes are both expensive and full of helpful information, free cast sheets are usually provided. Tonight the evening will feature a panel debate, live performance and questions from our studio audience - all of which will be streamed live on the Telegraph website from 8pm at telegraph.co.uk/thebigquestion