Conceal me what I am, and be my aid
For such disguise as haply shall become
The form of my intent. I’ll serve this duke.
Thou shalt present me as an eunuch to him.

– William Shakespeare

Twelfth Night, Act 1, Scene 2. Viola, to overcome her high-pitched woman’s voice while disguised as a man as a servant to Duke Orsino, comes up with the clever double deception of pretending to be his eunuch – a man who has been castrated. She asks the Captain to help her.