Bec posted a beautiful image of her eldest daughter, writing: "Happy Birthday to my style icon! @miarebeccaofficial15 today! ❤️"
The caption speaks for itself - were we this cool at 15? We could only wish...
Meanwhile Lleyton also shared a picture of his daughter on her big day, writing: "Happy 15th B'day to my beautiful girl @miarebeccaofficial 💞 #ProudParents."
There's no denying Mia is taking more and more after her mother in the looks department.
As for Bec's career in acting, well, that much remains to be seen for Mia.
But little sister Ava on the other hand is already a shoo-in for a successful career in front of the camera.
With a managed Instagram account, the 10-year-old has already partaken in several professional shoots.
She's also a natural in front of the camera - perhaps a stint on Home and Away is also on the cards...?
This article originally appeared on our sister site Now To Love.