telling my crush I like him.

Literally right now we are playing 20 questions and he asked me my crush. I said I can't say ATM cause idk about it. I asked him and he does have a crush on a girl. I'm scared he's gonna say someone else. We have been really close and flirting a lot lately. I would tell him I like him if he told me he liked me too. I want him to say his crush first. How do I tell him that I like him??? Help me.