Definition of what do you know (about that)? in US English:

what do you know (about that)?

phrase

North American
informal
  • Used as an expression of surprise.

    • ‘And what do you know, this evening my uncle turned up.’
    • ‘Well, what do you know; he is good for something besides eating and sleeping!’
    • ‘I follow Suki and Keith's plans and, what do you know, after the first month, I've lost 6 pounds!’
    • ‘The shares may be marooned at 22p but, what do you know, the good news just keeps on coming.’
    • ‘Well what do you know, she does listen to me once in a while.’
    • ‘Hey, what do you know, it's Grand Prix weekend in Montreal!’
    • ‘We stood outside Fenway Park for a bit, while the Boston Red Sox were playing the Anaheim Angels - and what do you know - the Sox went on to win the World Series.’
    • ‘I glanced at the door just as it opened, and what do you know?’
    • ‘But what do you know - it's a fine album, creatively mixed and structured, full of strong playing and rhythms that actually feel good.’
    • ‘So now it's 9 p.m. and I've turned back to the Niners game and - what do you know?’