What To Wear
~What to Wear to a Black-Tie Wedding~
Women should wear a formal floor-length gown or a sophisticated cocktail dress. Women may also wear elegant pantsuits.
Traditionally, men must wear a tuxedo but in this case men will have the option of wearing a tuxedo, or they can wear a formal dark suit, white shirt, and conservative tie. A black bow tie, black vest or cummerbund, and patent leather shoes are suggested if opting for a tuxedo but not required.
Here's some inspiration: