Movie Premieres.
A public ceremonial event featuring the cast, filmmakers and other invited press, all of whom, come to witness the very first showing of a movie they were involved in before it finally released in theatres.
Functioning as a way to draw maximum media attention, the theatrical red carpet event, alongside having the actors starring in the movies themselves attend, usually invited the most famous actors and actresses, models, movie critics, reporters from various Hollywood publications and even a few popular social media influencers that could spread good word about the movie.
A lot of the times too, most of these people they had invited were people that they were either currently working with, or had worked with before at some point or the other.
Sometimes, when the budget for a movie was really high and it could be afforded, some movie studios could even host more than one Movie Premiere.