Holly Madison is having a baby girl, according to her boyfriend Pasquale Rotella. 

Rotella, a Las Vegas party promoter, announced their baby's sex on Twitter on Tuesday, Oct. 16.

"Off to Amsterdam and I already miss my girls," Rotella tweeted to his 39,000 followers. The tweet was accompanied by a split image of two photos of the former "Girls Next Door" star's face hiding behind what appears to be a blanket, and a sonogram of their unborn child's fetus.

The announcement was a surprise. Last weekend, the reality star told the press that the couple did know the baby's sex but weren't ready to announce it yet.

"We're not telling anybody yet, but we found out and I'm really excited," Madison told US Weekly. "I'm really excited about decorating the nursery, so we've already started buying some things there."

Madison is expected to give birth sometime early next year. Last month, Madison shared how she delivered the news to her boyfriend that she was expecting- on her cellphone via text message.

"I texted him from the doctor's office, I knew he'd be so happy," she told Us Weekly. "We want six kids."

Madison has always expressed a desire to be a mother: she did so repeatedly when she ws one of Hugh Hefner's girlfriends. Their relationship was documented on the reality show "Girls Next Door" but Madison left the Playboy mansion after the Playboy founder refused to get married to her.

Madison gave fans a peek at her ever-expanding baby bump last weekend when she attended a picnic in Las Vegas. Her protruding belly was in full view as she stopped by the "Forever Home Family Picnic" event in Las Vegas' Freedom Park on Saturday. The picnic was meant to celebrate families who have rescued a shelter dog and provided it with a loving home.

CLICK HERE to check out photos of a pregnant Madison showing off her baby bump in Vegas this weekend.

Madison is preparing to retire from her "Peepshow" burlesque revue in las Vegas. The 32-year-old's last performance will be Sunday, Oct. 21. Coco Austin, who is married to "Law & Order: SVU" actor Ice-T, will replace Madison in "Peepshow."