Angelina Jolie has given birth to a son and daughter in Nice, France with partner Brad Pitt at her side.

The actress delivered her twins by Caesarian section at the Fondation Lenval hospital on Saturday.

The twins, named Vivienne Marcheline, after Jolie's late mother Marcheline Bertrand, and Knox Leon, weighed 5 pounds and 5 pounds 3 ounces respectively.

Jolie's obstetrician, Dr Michael Sussmann, is said to have told reporters the operation, which was slated for Tuesday, had to be moved forward "for medical reasons".

Sussmann tells People.com, "The babies are doing well. The operation went just perfectly. Angelina is in very good spirits. Brad Pitt was at her side. He was there and all was well."

He adds, "The mother and father are very, very happy."

Jolie and actor partner Pitt are already parents to adopted children Maddox, aged six, Pax, four, three year old Zahara, and biological daughter Shiloh, two.