Credit: Charles Eshelman/Getty Images.

The World's Sexiest Woman is now the World's Sexiest Mom.

Actress and men's magazine darling Megan Fox revealed on Facebook today that she and husband Brian Austin Green welcomed a son on Sept. 27.

"We have been very lucky to have had a peaceful few weeks at home, but I would like to release this myself before others do," she wrote. "I gave birth to our son Noah Shannon Green on September 27th. He is healthy, happy, and perfect. We are humbled to have the opportunity to call ourselves the parents of this beautiful soul and I am forever grateful to God for allowing me to know this kind of boundless, immaculate love."

RELATED: Megan Fox Bears Pregnant Belly

Fox kept her pregnancy under wraps until photos of her with a bulging belly revealed that she was expecting. The "Friends With Kids" star told Cosmopolitan in April that she's "always been maternal" and wants "at least two, probably three kids."

Fox and Green, the erstwhile David Silver on "Beverly Hills, 90210," married in June 2010. Green also has a 10-year-old son, Kassius, from a previous relationship.