Lopilato gave birth to the couple's first child early Tuesday in Vancouver, Canada.
The 37-year-old Canadian singer and the 26-year-old Argentine actress were married in 2011. The couple met in 2009 during a South American concert tour.
Buble is a Grammy-winning pop singer who has sold millions of albums, including "Crazy Love" and 2011's "Christmas." Lopilato made her name as a model and in Argentine sitcoms and soap operas.