But that's pretty much all we know!
According to Us Weekly magazine, the former tennis professional's wife Brooklyn gave birth to a son on Wednesday, 30 September, but the couple are keeping the name under wraps.
Neither has made any reference to the birth via Twitter.
Andy, 33, and actress-model Brooklyn, 28, announced in May that their first child was on the way, with Brooklyn sharing a cute image to Instagram of herself cradling her baby bump.
"So this happened… #the3ofus," she wrote.