This is the wording from June this year -
What to Wear: Gala Evening
From 6.00pm, we encourage you to join in the sense of occasion with eveningwear of dinner jacket, tuxedo, or dark suit with a regular tie or bow tie, or floor length dress, ball gown, cocktail dress, smart trouser suit, or formal separates. Guests are welcome to embellish their Gala Evening attire to fit the applicable theme of the evening. A range of gentlemen's formal wear is available to hire on board in the fashion boutique on Deck 3.
Of course, if you prefer to spend tonight in more relaxed attire, a selection of casual dining and entertainment venues are available for your enjoyment. Feel free to dress casually as you visit any of the following venues Kings Court, Golden Lion, Casino, Carinthia Lounge, and G32. Please note non-ripped, jeans are appropriate, but please refrain from wearing shorts, sports attire, swim wear or sleeveless t-shirts outside of the gym, spa and deck spaces.