The couple's one-year-old son Noah made the special announcement for his parents in a video shared via Facebook.
Noah goes over to his mum Luisana, who is laying across the floor with her bare belly on display.
With Britney Spears' 'Oops!… I Did It Again' playing in the background, Michael asks: "Who's that in there?"
Noah touches Luisana's baby bump and says "baby!"
Noah has some news to tell you ...Posted by Michael Bublé on Monday, 6 July 2015
Michael , 39, and Luisana, 28, married in March 2011 in Argentina. Their first child, son Noah, was born in August 2013.
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Copyright: Instagram @fearnecotton4