"Camila gave birth to our third child yesterday morning. Our son, Livingston Alves McConaughey, was born at 7:43 a.m. on 12.28.12," he wrote online Saturday night. "He greeted the world at 9 lbs and 21 inches. Bless up and thank you for your well wishes."
The couple, who married last June, are also parents to 2-year-old daughter Vida and 4-year-old son Levi.