Black-Tie is black accessories worn with the black jacket and trousers. The name black-tie is often used as a code to indicate that the event is formal. This generally refers to the jacket, as black tuxedo pants are typically all the same. The style jacket worn is commonly called the black dinner jacket. This is because its shape resembles an ordinary suit jacket. A tails tuxedo jacket does not qualify as a dinner jacket. With this style of tuxedo, a black formal vest or cummerbund is optional. If you are wearing the cummerbund, the bow tie is the only acceptable neck wear allowed. Therefore, in the absence of the cummerbund, the long tie may be worn. This also means that when wearing the long tie, there is no requirement to wear a vest. This is also considered black-tie. Additionally, when wearing the vest all formal neck accessories (long tie, bow tie, ascot or cravat) are acceptable. Ultimately you want the look of Tuxedo TQ.
However, some Black Tie formals allow for a creative Black Tie ensemble. See the link below.
The ominous but alluring “Black Tie” invitation arrives at your door. Do I wear the dark suit in my closet. Here are a few formal wear etiquette tips to keep in mind.
Black Tie Formals decoded by Tuxedo TQ.