Locklyn Kyla Vaughn, who weighed 7 lbs. and measured 20 inches long, was born at a hospital in Chicago, Vaughn's hometown. The actor's rep confirms the good news.
"Both of them couldn't be happier to welcome their sweet little girl into their family!" says a friend of the couple's.
It's a first child for both Vaughn, 40, and Weber, a Canadian real estate agent, who married in January 2010.
When Weber's pregnancy was announced in July, a source close to the Couples Retreat star told PEOPLE that the pair were thrilled about the baby, saying, "They're having so much fun together and they're so excited to be first-time parents!"
Vaughn stars with Kevin James in the upcoming The Dilemma, to be released on Jan. 14, 2011.