Jessica Simpson has sparked rumours that she too may be expecting after being with a ‘baby bump’ on her 28th birthday party in Sherman Oaks, California.

Jessica, who celebrated her birthday with her beau Tony Romo sporting a free flowing short sleeved, looking curvier than ever.

Nick Lachey’s ex-wife appeared to have larger breasts and arms than usual with a slight bump on her tummy, which she was trying to hide with a grey jumper, reports news.com.au.

“She definitely looked bigger than she usually does, and her breasts seemed to have swollen too … She also kept holding a grey jumper in front of her stomach, as if she was trying to hide something,” an onlooker revealed.

If the reports are true, then Jessica’s parents will become grandparents twice over, what with younger daughter Ashlee Simpson also expecting her first child with hubby Pete Wentz.