Brian (played by Michael York) is the main character of the 1972 musical Cabaret, based on the Broadway musical of the same name. Bryan, a young British writer, moves to Berlin in the 1930s and begins a relationship with American club singer/dancer Sally Bowles. As their relationship develops, there is a turn where after a weekend with Baron Maximilian that Brian reveals to Sally that he also banged Max. The three soon enter a closed triad relationship.
This is one of the first mainstream examples of male bisexuality in film after the fall of the Hays Code. While Bryan is a flawed character, the inclusion of his sexual awakening was a watershed moment in queer representation in American film.