Jade Jagger has announced she is six months pregnant.

The 42-year-old model, whose 21-year-old daughter, Assisi Jackson, is also pregnant, has revealed she is expecting her third child, as she awaits the arrival of her first grandchild. The British jewelry designer, who also has a 17-year-old daughter, Amba Jackson, with her ex-boyfriend Piers Jackson, proudly showed off her growing baby bump in a photograph on Instagram on Tuesday, and wrote, "Happy to announce this granny is going to become a mummy I'm 6 months pregnant xx double whammy this year.''

The new baby will be Jade's first with her DJ and art designer husband Adrian Fillary. The couple tied the knot in a lavish ceremony at the luxurious Aynhoe Park hotel in the Cotswolds, England in July 2012.

Jade's eldest daughter Assisi announced last year that she was expecting her first child with her chef boyfriend Alex sometime this year and told Hello! Magazine that giving birth at a young age ran in the family. "The women in our family just tend to have children young, it runs in the genes," she said. She added, "I don't drink, I don't smoke and I'm very settled." She also insisted her grandfather Mick Jagger was delighted by the news: "He said, 'Well done,' and I said, 'I didn't have to try too hard.'"