Representatives for both actors confirmed the marriage to The Associated Press on Thursday. Their publicists, Ken Sunshine and Nicole King, also confirmed that Garner is pregnant with her first child.
Sunshine and King would not give any other details.
The confirmation came after Us Weekly reported that Affleck, 32, and Garner, 33, were wed Wednesday at the Parrot Cay resort in the Caribbean islands of Turks and Caicos. The National Enquirer also released photos it claimed showed Garner arriving on the islands with her "Alias" co-star Victor Garber.
In stark contrast to Affleck's much publicized relationship with Jennifer Lopez, he and Garner have been tightlipped about their romance. Aside from appearing at a Boston Red Sox game last fall, they have stayed out of the public eye.
Reports in April about an engagement were never confirmed. In May, E! News reported that Garner was pregnant and the baby was due in November, but neither star confirmed that report.
This is first marriage for Affleck and the second for Garner, who divorced actor Scott Foley in March 2004 after 3 1/2 years of marriage.
Affleck and Lopez called off their September 2003 wedding and broke off their engagement in January 2004. Lopez married singer Marc Anthony later that year.
Garner and Affleck met while they were shooting the action flick "Daredevil," but they didn't begin dating until last year.
She has been filming the drama "Catch and Release" in Vancouver, Canada. Affleck will star as George Reeves, television's Superman, in the upcoming movie "Truth, Justice, and the American Way."
By Jake Coyle
By Jake Coyle