"My girlfriend Camila and I made a baby together," McConaughey writes. "It's 3 months growin in her womb and all looks healthy and lively so far. We are stoked and wowed by this miracle of creation and this gift from God, and so excited for the adventure that will come in raising this child, being mother and a father, and shepherding him or her through this life."
McConaughey adds: "Wish us the best, keep us in your prayers, and God bless evolution. Thanks for being fans of me and my work and now this new and miraculous chapter in my life, as me and Camila and our child do our best to just keep living."
He signs his message, "Wow, McConaughey."
McConaughey, 38, met Alves, 24, a Brazilian model whose family moved to L.A. when she was young, more than a year ago. Since then, they have been together constantly – and often in the Ocean – riding the waves last year from Australia, where he filmed Fool's Gold, to the Bahamas, where he shot the comedy Surfer Dude.
"He's out of his mind!" says his rep Alan Nierob of the pregnancy. "He is euphoric. He couldn't be happier."
Longtime McConaughey pal Mark Gustawes, who is producing Surfer Dude, says the couple are "incredibly happy."
"I can only hope that one day the love I have with the woman carrying my child is equivalent to the love Matthew and Camila share," says Gustawes. "That's a tall bar. In my opinion, the child will be raised with more love than it knows what to do with."