Who is Mnester from Claudius the God and His Wife Messalina and what is their importance?

Mnester works in theatre and is a popular actor. He is also popular with Messalina, who lusts after him. While Claudius is away fighting in Britain, Mesalina proposes a romantic arrangement, which Mnester promptly refuses. When her husband returns, Messalina complains that the actor is insolent, which leads to Claudius commanding the young man to obey his wife in all things. He, thus, becomes her lover..... something I doubt Claudius planned on when he issued the directive.