A spokesman for Angelina Jolie on Tuesday said the actress is "doing great" following reports that she has checked into a hospital in Nice, France, ahead of the birth of twins.

Media reports said the 33-year-old Oscar winner, whose partner is actor Brad Pitt, was admitted to the Lenval Hospital yesterday, citing a hospital spokeswoman.

Jolie's Los Angeles spokesman said in an e-mail to Reuters that she is "doing great, very healthy and happy," but he declined to elaborate or confirm her medical treatment.

"Ms. Jolie came to the hospital last night as part of a pre-planned rest period, before she gives birth," Nadine Bauer, spokeswoman for the hospital, told In Touch Weekly magazine.

"The visit has been planned for a long time, there are no complications. She is just resting," Bauer added.

Neither the French hospital nor Pitt's US representatives were immediately available for further comment.

Jolie, star of current hit movie "Wanted," and Pitt, of "Ocean's Eleven" fame, are two of Hollywood's biggest stars. They went public with their relationship after co-starring in the 2005 film "Mr. & Mrs. Smith."

They have one biological daughter together, Shiloh, who was delivered by Caesarean section two years ago in the southern African nation of Namibia.

The couple also are the parents of three adopted children -- daughter Zahara from Ethiopia, son Pax from Vietnam and son Maddox from Cambodia.

One US celebrity magazine has said Jolie is pregnant with two girls while a rival publication had it as a boy and girl. A British tabloid published the supposed names of the yet-to-be-born children.

Reports also have speculated that Jolie was due to give birth in mid-July or August, but one US celebrity TV show has said that Jolie already had the babies.

None of the reports could be confirmed.

A visibly pregnant Jolie confirmed at the Cannes film festival in May that she was having the babies. It was her co-star in the movie "Kung Fu Panda," Jack Black, who said in interviews at Cannes that she was expecting twins.