Britney Spears is three months pregnant, reports celebrity portal Femalefirst.

The pop diva, who has made no secret of her desire to start a family with second husband Kevin Federline, will reportedly announce her pregnancy within the next couple of days.

"Britney Spears is not a girl, soon to be a mommy. She's pregnant. Look for the announcement any day now," gossip columnist Norm Clarke was quoted by the website as saying.

Britney has reportedly quit smoking after finding out she was expecting her first child.

Earlier this year, she sparked pregnancy rumours after she bought herself a maternity swimming costume from an exclusive Los Angeles boutique.