This weekend my fairy godmother is taking me (and her daughter) to the opera. I'm fortunate enough to have attended a few ballets in my time, many when I was little enough to get away with wearing a poofy skirt that rivalled some of the dancer's tutus, but this is the first opera I've been to, and I'm not entirely sure what to wear! Whenever I see people going to the opera in films or on telly they're always dressed to the nines and I don't want to be under- dressed, but neither do I want to be over-dressed and feel self-conscious.

I feel like I should dress a bit fancier than I do for going to the theatre, but does anyone have any suggestions? Do I go all-out and wear my glitteriest earrings? What about hemlines? Help!

ETA: Thanks for all the suggestions! I have some great dresses in my wardrobe that are all contenders and am suppressing the urge to just use this as an excuse to buy yet another one. Thanks for all your help, you guys are awesome.