It means to tell the secret or joke to someone else
Let Somebody Know was created in 1995.
Leave someone alone means stop pestering somebody. Let someone alone means let somebody be by himself or herself. The two phrases originally meant the same thing, so you will sometimes find either of them meaning to allow someone to be by himself or herself, but that is increasingly unlikely with "Leave me alone." "Let me alone" can also be used with the stop bothering me meaning.
Tell her a joke!
Saying they let the FedEx guy add a joke to the show in the opening crawl is a joke in itself. They didn't actually do that.
The phrase "cat out of the bag" means a secret or surprise has been revealed, usually unintentionally. It stems from times when people would sell piglets in bags, and sometimes dishonest sellers would substitute a cat. If the cat escaped from the bag, the trickery would be exposed.
It is what you show somebody to let them remember what to say.
It seems like there may be a typo in your question. Did you mean to ask about "idiom," which refers to a phrase or expression that has a meaning different from the literal interpretation of the words used?
Okay let's hear it... this better be good...
Van Zant - Help Somebody ---- I never let a cowboy make the coffee Yeah, that's what granny always said to my granddad And he'd say, "Never tell a joke that ain't that funny more than once
Dont let somebody steel it.
If he (or she) is an "ex," haven't you already split up? Somebody's been "let down" by now.
It means to let go