The adorable little tots are featured in a 1985 vintage clip in which they are taking part in an official photo shoot at Kensington Palace.
The young brothers were aged 3 and 1 at the time.
The video also shows Prince Charles fooling around with a handkerchief to make the children look in the right direction of the camera, while the late princess Diana looks radiant as she poses for the cameras.
At one point, William is seen dabbing his mother’s face in an attempt to re-do her make up.
The two boys behave like any other children their age, scampering away, hiding under tables and running away from their parents’ arms.