'It's no Beyonce post... but our best adventure yet is on it's way,' the post began. 'Baby Phillips Rumble is due early July and we are beyond excited, slightly terrified but utterly blessed.'
She added: 'We can not wait to meet our little miracle. I've always dreamed of being a mother, but never knew it could be... read about our journey in the coming weeks on my blog #19weeks #pregnant #babyphillipsrumble.'
The Sydney-based pair announced their engagement in 2013 during a trip to Hong Kong.
The former New Zealand's Next Top Model guest judge married her 33-year-old husband one year later.
Nikki previously said she wasn't certain that kids were in their future.
In 2009, the statuesque blonde was diagnosed with stage three cervical cancer following a routine pap smear.
Doctors were able to remove the cancerous cells and years later, the model is now believed to be cancer-free.
The blonde beauty met Dane while undergoing post-operative testing for cancer and she once told the discontinued Cleo magazine that he was supportive and 'amazing' throughout the ordeal.
'If I can't have kids he is fine with that,' she said.
Last year, Nikki relaunched her By Nikki Phillips blog, which features red carpet events, fashion and travel.
