Idiom of the day :- Let someone in on something

Usage, examples and definition of the Idiom :-

I’ll let you in on something : Barton is very fond of Emma. See, he’s always doing something to impress her. Right now he’s entertaining her. ‘Gee, how did you do that ? Let me in on your trick !’ she asked. To let someone in on something is to share information or a secret with someone.