Holly Madison is having a girl.

The former 'The Girls Next Door' star's boyfriend, Pasquale Rotella, accidentally let slip the sex of their baby in a tweet earlier this week.

The party promoter wrote: ''Off to Amsterdam and I already miss my girls.''

When a follower congratulated him, he added: ''We are very excited!''

Holly had previously said they had found out the sex of the baby but were keeping it secret, although she has been taking inspiration for baby names from Gwyneth Paltrow, who has children Apple, eight, and Moses, six.

She said: ''I don't want to say what the names are, but I will say that they're very unusual. Kind of Apple-ish, along those lines.

''I don't like common names at all. If I've heard it before on somebody more than one time than it's out.''

The 32-year-old - who has previously dated Hugh Hefner - is preparing to step down from her role in raunchy Las Vegas strip show 'Peepshow' and is searching for new ways of keeping fit as her pregnancy progresses.

She explained: ''There's a lot of dancing on the show [to keep me fit]. Also, I've been getting pregnancy yoga and pregnancy Pilates DVDs for my house and have been trying to work out every day and be healthy.''