He acts like a stage-door Johnny waiting for the lead actress.
stage-door Johnny
idiomA man who is infatuated with one or more theatrical actresses and who routinely lingers in and around theatres in an effort to meet and form relationships with the female(s) of his affection.
The security guard told the persistent stage-door Johnny to leave the theater entrance after the show ended.
The aging actor watched with amusement as a young stage-door Johnny lingered in the shadows, clutching a bouquet of roses for the leading lady.