Voice actor Angelina Jolie and Brad Pitt arrive for the screening of the animated film 'Kung Fu Panda' by directors Mark Osborne and John Stevenson at the 61st Cannes Film Festival May 15, 2008. [Agencies]

Angelina Jolie's twins may take a few more weeks to arrive, media quoted the actress's doctor as saying Thursday.

Dr. Michel Sussman said the actress had checked into the hospital just for closer surveillance rather than for birth, adding that Jolie "will stay in the hospital until the birth."

"She is very well, and she's okay. Brad and Angelina want everyone to know that everything is going well. Everything is normal," Sussman assured.

Sussman gave no due date about birth of Jolie's twins, saying they are expected to arrive in the weeks to come.

"This is something you can't program, you never know for sure," Sussman said.

The 33-year-old Oscar winner already has one daughter with actor Brad Pitt -- 2-year-old Shiloh Nouvel Jolie-Pitt.

The couple have also adopted three more children - Cambodian-born son Maddox, daughter Zahara from Ethiopia and Pax from Vietnam.