ET confirms that Angelina Jolie has given birth to a baby girl and boy in Nice, France. Dr. Michel Sussmann, the obstetrician who delivered the twins, said Angelina delivered a boy named Knox Leon and a girl named Vivienne Marcheline by Caesarian section Saturday night.

"Everything is going well," Sussman said, with Angelina expected to stay in the hospital for a few more days. "The mother, the babies, the father are doing marvelously well," said Sussman, who added that Knox weighed 5.02 pounds, while Vivienne weighed 5 pounds.

The Caesarean procedure was moved up from its original date "for medical reasons" so the babies could be born "in the best conditions."

Angelina's partner Brad Pitt was present for the procedure, which took place at the seaside Lenval hospital in southern France. Sussman said Pitt was pleased to be present for the birth and described the actor's demeanor as "perfectly calm" and "very emotional." According to People.com, Brad even cut the babies' umbilical cords. "He was my assistant," the doctor tells People.

The mayor of Nice, Christian Estrosi, congratulated Brad and Angelina and said he was honored that "the most famous couple of the world" had chosen his city as the place to have their twins. Estrosi proudly held up a copy of the birth certificates for the press on the steps of the hospital.

The twins join Brad and Angelina's established brood of Maddox, 6; Pax, 4; Zahara, 3, and Shiloh, 2.