Jessica Simpson, in her Halloween costume
10/31/2011 at 07:00 PM EDT
Believe it: Jessica Simpson
is expecting a baby!
"It's true – I'm going to be a mummy!" she Tweeted Monday, posting a photo of herself
dressed up as such for Halloween and cradling her baby bump.
The singer and fashion designer has been the subject of pregnancy buzz
for weeks after photos surfaced of her shielding her midsection
at the airport.
Simpson, 31, has also been recently photographed in New York City
, showing off what appeared to be a burgeoning baby bump in form-fitting clothing.
This will be the first child for Simpson, who has previously expressed her desire
to have fiancé Eric Johnson's babies.
"I definitely see myself having a family with him, so that's exciting to think about," Simpson said shortly after her beau, a former NFL athlete, popped the question
The baby on the way will be the second grandchild for Simpson's parents Joe and Tina, who first became grandparents in Nov. 2008 when daughter Ashlee Simpson
and her ex-hubby Pete Wentz
gave birth to son Bronx.