Pitt's manager, Cynthia Pett-Dante, told The Associated Press: "We have no comment except the story is not true."
Several celebrity news outlets also reported the story was false. A spokeswoman for "Entertainment Tonight" did not return a call for comment Friday.
Jolie has said previously that her twins are due in August. She and Pitt have four other children: 6-year-old Maddox, 4-year-old Pax and 3-year-old Zahara, who are adopted, and 2-year-old Shiloh.
In southern France, where locals say the couple recently moved, officials at the Etoile Maternite Catholique de Provence in Aix-en-Provence, one of the region's top maternity clinics, said that Jolie had not been there and did not appear scheduled to come.
Privacy rules about health matters are extremely strict in France.
The pair recently moved into the Miraval Estate villa in the French hamlet of Correns, in the Provence region, according to the mayor and a local inn owner.
Traditionally, the region has lured tourists mostly for rock-climbing excursions on the rolling hills of the verdant region and leisurely strolls in its quaint medieval villages.
Mayor Michael Latz trumpets Correns as France's first town where all locally grown produce is organic - and his villagers teem with pride about that reputation, and seem mostly bemused about the invasion of Hollywood buzz.
"I like to joke that I'm happy to be able to contribute to the image of Angelina Jolie and Brad Pitt, because Correns is so well known," Mayor Michael Latz said with a smile outside the ochre-colored town hall.
Latz said that Tom Bove, an American businessman who owns Miraval, recently told him that Jolie and Pitt had agreed to a three-year lease on the property, known for producing high-quality organic wine.
The couple is "in the process of moving in," said Latz, adding that he hadn't met them and knew nothing about whether Jolie had given birth or not.
"They are people who I hope will live normally here," he said. "I would think the choice of Brad Pitt and Angelina Jolie ... is tied to the quality of life in Correns."
Latz also rejected speculation about an imminent wedding, and said that under French law they'd need to alert local authorities if they want to officially tie the knot here.
Security guards were blocking the gates to the estate Friday, while a postal truck and other maintenance vehicles regularly passed in and out. The castle and accompanying buildings can't be seen from public roads.
Onno Stijl, owner of the L'Auberge du Parc inn, said it was a good thing they were moving in and could help business. He said he gets his wine from the estate's vineyards.
"It's a couple living here now like everyone," he said.
The area, he said, "is a bit isolated but that gives it a certain ... privacy."
According to its Web site, the Miraval estate dates from pre-Roman times. It includes fountains, aqueducts, moats, a lake and vineyards that produce an organic wine distributed worldwide.
Pitt and Jolie may be Miraval's first movie stars in residence, but Miraval has seen its share of rock stars. The estate includes a studio which has hosted the likes of Sting, the Cranberries and Pink Floyd, who recorded tracks for "The Wall" album there.