The Hollywood couple have been regularly photographed with Jolie's adopted children MADDOX and ZAHARA over the past year, but both have refused to confirm the nature of their relationship.
After weeks of rumours of Jolie's pregnancy, America's People magazine quoted the actress as telling a charity worker in the Dominican Republic, "Yes, I'm pregnant."
A statement from Pitt's publicist Cindy Guagenti issued yesterday (11JAN06) confirms the actor is set to be a father and refers to him and Jolie as "they" for the first time.
Guagenti says, "I can confirm they are expecting. There isn't a lot more to say."
Pitt, 42, is currently in the process of legally adopting 30-year-old Jolie's Cambodian son Maddox, four, and Ethiopian daughter Zahara, 10 months and the GIRL, INTERRUPTED beauty has petitioned for the tots' surnames to be changed from Jolie to Jolie-Pitt.
When asked for Aniston's response to the pregnancy news, a spokesman for the former FRIENDS star says, "Jennifer is not in the practice of commenting on the lives of other people."
Meanwhile, Jolie's estranged father, actor JON VOIGHT says, "Angie is my daughter and I am always wishing the best for her."