The loved up twosome tied the knot on June 9 at their home in Texas and are already parents to Levi, four next week, and Vida, two.
The Magic Mike actor confirmed the news on his Twitter.
“Happy birthday America, more good news,” he wrote. “Camila and I are expecting our 3rd child. God bless, just keep livin.”
Camila, 29, also posted the message on her social networking page clearly delighted to be adding to their brood who had served as ringbearer and flower girl at their nuptials.
“Somehow they both seem to understand what we are doing on a spiritual level,” she gushed about her children.
The couple got together after meeting in a Los Angeles bar in 2006 and Matthew popped the question on Christmas Day 2011.