guess what

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guess what

A question that precedes a surprising announcement. It is a set phrase and is often but not always rhetorical. Guess what? Your mother is coming to visit this weekend after all. A: "Guess what?" B: "I have no idea—do you have news?"
See also: guess, what
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

Guess what!

Inf. a way of starting a conversation; a way of forcing someone into a conversation. Alice: Guess what! Bob: I don't know. What? Alice: I'm going to Europe this summer. Bob: That's very nice. John: Guess what! Jane: What? John: Mary is going to have a baby. Jane: Oh, that's great!
See also: guess
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

ˌguess ˈwhat

(informal) used to introduce something surprising or exciting that you want to tell somebody: Guess what, Angela’s getting married next month!
See also: guess, what
Farlex Partner Idioms Dictionary © Farlex 2017
See also:
References in classic literature ?
Look again, and guess what those are," answered Uncle Mac, chuckling and enjoying it all like a boy.
God keep me from ever seeking to guess what he aims at; I confine myself to watching what he does, and that is well enough.
Charades is a guessing game where participants need to act out the word or phrase while others guess what it is.
Well, these days I'm trying to guess what happened to the home business in January and February this year.
For the next competition, fans will have to guess what figure the band's hotel room numbers will add up to.
INSTEAD of Guess Who, let's play Guess What! Here we go: What's now on DVD, but is still as miserable, woeful and unfunny as when it was on at the cinema?