The Colombian singer-songwriter has proudly introduced her baby boy to the world by uploading a picture showing Pique cradling his son and planting a kiss on his cheek with the message: "Meet our baby boy Milan".
Two weeks ago the star and Pique invited fans to join an online baby shower in support of "the world's most vulnerable babies".
"To celebrate the arrival of our first child, we hope that, in his name, other less privileged children in the world can have their basic needs covered through gifts and donations," the couple said in a statement.
"Every expectant parent around the world shares all the same hopes and dreams for their children that we do.
"Yet many don’t share the same opportunities. Together we know we can change that. Thank you for sharing this unforgettable moment with us."
Milan is the couple's first child.