Jade, 42, posted a photo on Instagram with her growing baby bump in full view. The mother-of-two is pictured standing side on in a black strappy top and shorts and beaming at the camera.
"Happy to announce this granny is going to become a mummy, I'm 6 months pregnant xx double whammy this year," wrote Jade alongside the photo.
Jade and her DJ husband Adrian Fillary tied the knot in July 2012 at a country mansion in the Cotswolds, proudly watched by her parents, Mick Jagger and Bianca Jagger.
Jade's daughter Assisi, 21, recently revealed to HELLO! magazine that she was expecting her first child with her chef boyfriend of three years Alex Key.
Assisi's baby is expected to be born at the end of April, making her pregnant mother Jade a grandmother-to-be – and Sir Mick a great-grandfather for the first time.
Jade was just 20 when Assisi was born, and it seems giving birth at a young age runs in the family.
"The women in our family just tend to have children young, it runs in the genes," Assisi told HELLO!.
"I grew up quite quickly and wouldn't have considered having a child if I was doing what my friends are doing at this stage, messing around," she added. "I don't drink, I don't smoke and I'm very settled."