The 39-year-old actress and her producer husband Scott Stuber - who tied the knot in September 2011 - welcomed their first child on 19.06.12, according to Us Weekly magazine.
The baby weighed just over 7lbs and his name has not yet been revealed.
Molly previously revealed she conceived while on honeymoon and couldn`t wait to become a mom.
Writing on her official website, she said: "I am absolutely, positively, downright over the moon to announce that we are pregnant! There are simply no words to describe the feeling . I finally get what they mean when they say pregnant women glow.
"Our little bundle of joy is a honeymoon baby, due at the end of June. A first pregnancy is a nerve-wracking experience of course, but mostly we are just thrilled and excited. We can`t wait to meet him or her."
The blonde beauty also admitted she chose an unconventional way of telling her 43-year-old husband he was going to become a father, and opted for delivering the news via a fortune cookie.
Molly added: "I hijacked the fortune cookie and typed a new message so that when he opened his cookie at the end of the meal, he found out he was going to be a daddy.
"You can only imagine how nervous I was during the entire meal (I think I ate a total of two bites), but the look of surprise and pure joy on his face was priceless."