Even though his parents are both U.S. citizens, Knox Léon Jolie-Pitt and his sister Vivienne Marcheline were born in Niece, France, at the Fondation Lenval hospital overlooking the Mediterranean Sea. Given their parents' fame, the world was eagerly awaiting the twins' arrival, and so was their mother, Angelina Jolie. She was advised to stay at the hospital for surveillance two weeks prior to their birth (via People). When the twins finally made their arrival on July 12, 2008 via cesarean section, Jolie and her husband, Brad Pitt, were elated.

Michel Sussmann, the doctor who delivered the twins, later told Europe 1 radio (via Reuters) that, despite having years of experience delivering babies, he couldn't help but feel a little nervous when the time came to deliver the twins. "It wasn't pressure on a medical level, because I have been practicing for a certain number of years, but it's true that there was pressure due to the couple's fame," he said at the time. He told People that Pitt was at Jolie's side during the birth, and even though he was "perfectly calm," emotions ran high when he heard the twins' first cries.

Outside the hospital, reporters gathered to welcome Knox and his sister and hopefully get a glimpse of the Jolie-Pitt family as they left. The Nice Matin newspaper dedicated several pages to their birth, and Nice's mayor, Christian Estrosi, even signed the twins' birth certificates.