Victoria Beckham "never properly fitted in" with her school friends.
The 42-year-old fashion designer wishes she could have told her younger self that despite how much she was "struggling" at the time, things would turn out alright in the end.
Penning a letter to her younger self, she shared: "I know you are struggling right now. You are not the prettiest, or the thinnest, or the best at dancing at the Laine Theatre Arts college. You have never properly fitted in, although you are sharing your Surrey school digs with really nice girls.
"You have bad acne. You think the principal has put you at the back of the end-of-year show (in a humiliatingly bright purple Lycra leotard) because you are too plump to go at the front. (This may or may not be true.)"
And the former Spice Girl - who has Brooklyn, 17, Romeo, 14, Cruz, 11, and Harper, five, with her husband David Beckham - also had some advice for her younger self in the height of her fame.
Writing for British Vogue magazine of her years in the chart-topping girl group, she added: "You are going to have so much fun with your clothes - PVC catsuits; chokers that say absurd things; weird spiky blonde hair. It will never occur to you that you appear ridiculous.
"You will turn up at awards ceremonies resembling a drag queen. But I look back at you and smile. It will add interest to your life to go from one extreme to another. I love the fact that you will feel free to express yourself."