People magazine reports, the couple got married Monday at a Beverly Hills courthouse.
Alba and Warren got engaged in late December following her announcement that they're expecting a baby.
They met on the set of "The Fantastic Four" when Warren was working as a director's assistant.
Their wedding was so quiet that even her brother, Josh Alba, apparently was caught off-guard.
When reached by Us Weekly magazine with the news, he responded: "My sister!? I'm going to have to call her!"
Alba and Warren are expecting a daughter this summer.
