The "Alias" star and boyfriend Ben Affleck are expecting their first child in November, according to E! News.
Garner's publicist, Nicole King, didn't immediately return a call from The Associated Press on Monday. Affleck's representative, Ken Sunshine, refused to comment.
Last month there was speculation that Garner and Affleck are engaged, though neither star has confirmed those reports. The couple met while shooting the action flick "Daredevil," but didn't being dating until 2004.
Garner and the 32-year-old Affleck have kept their relationship private, as opposed to his much publicized engagement to Jennifer Lopez, which was called off in January 2004.
Garner, 33, was previously married to actor Scott Foley. They divorced in March 2004.