Is Jessica Simpson pregnant?

Reuters

BABY BUMP? Jessica Simpson's fuller figure has sparked rumours the pop star is pregnant.

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Jessica Simpson has sparked rumours she is pregnant.

The Come on Over singer was photographed with an apparent baby bump as she celebrated her 28th birthday in Sherman Oaks, California.

Wearing a flowing, short-sleeved brown and white dress, topped off with a cowboy hat, Jessica grinned broadly as she walked along with friends, but appeared to have larger breasts and arms than usual.

An onlooker said: "She definitely looked bigger than she usually does, and her breasts seemed to have swollen too. It could have just been down to a big lunch, but it looked like more than that. She also kept holding a grey jumper in front of her stomach, as if she was trying to hide something."

Jessica - who is divorced from singer Nick Lachey - has reportedly been finding it hard to disguise her jealousy about her 23-year-old sister Ashlee's news she is expecting her first child with husband Pete Wentz.

A source said: "Jessica has yearned for a baby for years. She's told friends that she can't wait to be a mom and has even joked that if she has to, she'll resort to making her hairstylist pal Ken Paves the adoptive daddy.

Jessica never imagined that her tomboy younger sister would have a baby first. It would be very hard for her not to be jealous."