The royal family attended a memorial service for the Queen Mother and Princess Margaret. Photo: Getty
She may have recently lost two stone, but princess is in good company among fans of the figure-shaping shorts and tights, with everyone from Beyoncé to Sarah Jessica Parker having previously flashed theirs.
And the brand is so successful that, at 41, its founder, Sara Blakely, was recently the youngest self-made woman to make it on to the Forbes' Billionaires list.