"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 greeted the world at 9 lbs. and 21 inches," McConaughey announced via Twitter.
"Bless up and thank you for your well wishes. Happy New year, and just keep livin, Camila and Matthew McConaughey."
The pair, also parents to Vida, who turns 3 next month, and Levi, 4, announced the pregnancy just one month after their June nuptials in Texas.