France's first lady Carla Bruni-Sarkozy attends arrival ceremonies for Chinese President Hu Jintao at Orly airport, near Paris in this Nov 4, 2010 file photo. [Photo/Agencies]

PARIS - French First Lady Carla Bruni has fanned rumours she is pregnant, clutching a shawl to her belly during a newspaper interview and fending off inquiries with the words "my lips are sealed to protect something..."

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Asked by a Le Parisien reporter if the answer would be known six months from now, Bruni giggled and said "Yes".

A pregnancy could be a public relations boon to the first couple as Nicolas Sarkozy struggles with some of the lowest presidential popularity ratings ever seen in France a year before a likely battle for reelection.

Answering questions from readers of Le Parisien daily in a question-and-answer session published on Monday, 43-year-old Bruni said she regretted not being able to fully discuss pregnancy rumours that surfaced last week after reports in Closer and VSD magazines.

"I would love to speak woman-to-woman of my family life, my personal dreams, of the details of certain things. Moreover I am very talkative. But here, in a way, I have my mouth sewn shut," Bruni told a female reader who asked about the subject.

Bruni said that were she alone with the woman in a cafe she would talk freely, but could not publicly discuss a subject that would overshadow issues Sarkozy was working on as president.

"(It's) not because of arrogance or a desire to be secretive. My lips are sealed to protect something and to protect all the work (Sarkozy) does," Bruni said. "I would really like to talk about it but then it would take over everything else... So I will not answer."

She further fanned the rumours by clutching a voluminous shawl to her middle in every photograph taken by the newspaper -- uncharacteristic behaviour from the former model who normally shows off her slender figure in close-fitting clothes.

Bruni, who has a son from a former relationship, has often said she would like to have a child with Sarkozy, whom she married following a whirlwind romance after he became president in 2007 and his former wife Cecilia immediately left him.

Political commentators say a pregnancy could boost the image of the presidential couple among the French, many of whom dislike Sarkozy's flashy image and found his public courtship of Bruni, a former model and pop singer, to be in bad taste.

If Bruni is expecting, it would be Sarkozy's fourth child after the three sons he has from his two former marriages.