Publicist Cindy Guagenti released a statement late Friday saying the couple is seeking to have the children's names changed to Zahara Jolie-Pitt and Maddox Jolie-Pitt, People magazine reported.
"Brad Pitt is in the process of becoming the adoptive father of both children," the statement said.
Jolie adopted Maddox, 4, and Zahara, 11 months, as a single mom. They have all been living with Pitt at his home in Malibu, Calif., since his split with Jennifer Aniston this past summer.
There are no plans for the couple to marry at this time, Guagenti said.