Millie, 23, added: "Old family photos! #throwback #daddysgirl."
In the snap Mr Mackintosh proudly holds a young Millie in his arms. Talk about family likeness, Millie and Mr Mack look like two peas in a pod!
Millie's great-great grandfather created the toffee company Mackintosh's, and her great-grandfather invented Quality Street. She grew up in Bath with her dad and mum Georgina in Bath.
As well as leafing through old snaps over the weekend, Millie spent some time with her pooches and a friend's baby, Lullah, who she clearly adores.
Former Made In Chelsea star Millie taught Lullah how to post selfies and helped with bath time... So sweet!
She said: "Lullah is learning about selfies! #baby #selfie #belfie"
Millie is clearly feeling a bit broody. But she and new husband Professor Green denied rumours that she was pregnant after returning from their honeymoon recently, so it could be a while yet before we get to see mini-Millie and Pros!
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