Mick Jagger is a very proud father of eight children, and is even a great-grandfather – but that hasn't stopped him from expanding his family further!The Rolling Stones musician, 77, took to Instagram this week to introduce a new member to his clan, albeit of the furry variety.MORE: Sir Mick Jagger's granddaughter Assisi expecting second childMick could be seen smiling in the candid snapshot sat on a floral sofa with a guitar resting nearby, and holding an adorable black kitten.