what do you know!

(Well,) what do you know!

Inf. a way of expressing surprise at finding something that is unexpected; an expression of mild surprise at something someone has said. (No answer is expected or desired.) Andy: Well, what do you know! Here's a brand new shirt in this old trunk. Bob: I wonder how it got there. Tom: These two things fit together like this. John: Well, what do you know!

(Well) what do you know!

something that you say when you are surprised by a piece of information
Usage notes: This phrase is often used humorously to mean the opposite.
And they're getting married? Well, what do you know! (humorous) Well, what do you know! The Raiders lost again.