Mick Jagger, 70, is now a great-grandfather, according to Hello magazine

The mag is reporting that the rocker’s granddaughter Assisi gave birth to a baby girl whose name has not been announced. It is the first child for 21-year-old Assisi and her chef boyfriend Alex Key.

Assisi’s mother, Jade Jagger, 42 is pregnant with a baby boy who is due next month. Jade was just 20 when her daughter was born to her and former boyfriend artist Piers Jackson.

“The women in our family just tend to have children young, it runs in our genes,” Assisi told the magazine in an earlier interview. “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. I don’t drink, I don’t smoke and I’m very settled.”

But don’t expect Sir Mick to be called great-grandpa anytime soon.

“I imagine it’s nice to be a great-grandad – although I’m not sure he likes the idea of getting old, or being called one,” Assisi admitted. “I call him Mick – I wouldn’t start calling him grandpa.”

A rep for Jagger did not return FOX411's request for comment.